“Jon Lester is bona fide,” Royals manager Ned Yost said. “He’s a premier lefty in this league and he showed why.”

The Royals are hopeful Duffy can develop into one. Duffy held the Red Sox to two runs and five hits in six innings, leaving with the Royals trailing 2-0. Jason Varitek’s first triple since June 24, 2007, drove in the first Boston run in the fifth. Darnell McDonald homered in the sixth for the other run off Duffy, who was making his 17th big league start.

“Duffy pitched a great game,” Yost said. “He was on the attack. He was throwing strikes and getting ahead in the count. He hung a curve to Varitek for the triple, and he tried to go inside to McDonald and just got too much of the plate, but otherwise he didn’t make too many mistakes. He kept his pitch count in check. He was really very, very good.”

But Lester was better.

“He’s got good enough stuff to put you away and get ahead in the count, and he’s got a cutter he can use to get back in the strike zone and get back even,” said Royals first baseman Eric Hosmer, who went 0 for 3 with a walk. “He mixed it up. He threw a good game. You’ve got to tip your cap to him.”

Duffy (3-8) struck out three and walked two. He is 0-4 in four August starts.

“His stuff is good, but we finally broke through,” Red Sox manager Terry Francona said.

Duffy was much sharper than his last outing, when he gave up eight runs in three-plus innings of a loss to the New York Yankees.

“I think it was a step forward personally,” Duffy said. “It’s kind of hard to think about it that way when you lose, but personally, my efficiency was a lot better than it was against the Yankees.”

Carl Crawford also hit a solo home run for the Red Sox.

Lester (13-7) has allowed two runs and six hits in 13 innings in his past two starts to beat Kansas City and Tampa Bay. He is 5-1 with a 1.30 ERA in seven career starts against the Royals.

McDonald, who had three hits, hit his fifth home run of the season in the sixth on an 0-2 pitch from Duffy. Aaron Crow gave up a home run to Crawford, his eighth, in the seventh inning.

Ryan Lavarnway, Adrian Gonzalez and Jed Lowrie had RBIs in the eighth as the Red Sox scored three runs off Louis Coleman, one of four rookie pitchers the Royals used.

Johnny Giavotella led off the Royals seventh with a triple and scored on Mike Moustakas’ single for the only run off Lester, who was replaced by Daniel Bard after 113 pitches with two runners on base. Bard retired the next three hitters

The Royals loaded the bases on two walks and Lowrie’s error in the second, but Lester retired Alcides Escobar on a comeback to end the inning.

Lester, who no-hit the Royals on May 19, 2008, did not allow a hit until Perez’s single with two outs in the fourth.

Notes: CF Jacoby Ellsbury was out of the Boston lineup for the second straight game with a contusion in his back after being hit by a pitch Friday. It is questionable whether Ellsbury will return Monday when the Red Sox open a four-game series at Texas. “It doesn’t make a lot of sense to get him back out there too early,” Francona said. “He’s still pretty sore.” … The Royals are off Monday before playing 17 of their next 20 games on the road. … RHP Bobby Jenks, who has been on the disabled list twice this season with back tightness, is scheduled to throw 20 to 30 pitches Monday in a simulated game at the Red Sox complex in Fort Myers, Fla. … DH David Ortiz, who has missed the past seven games with bursitis in his right heel, is hitting off the tee and soft toss in the cages, but is still wearing a boot on his foot. … Red Sox LHP Erik Bedard, who starts Monday, is winless in his past eight starts against the Rangers, although he has allowed three earned runs or less in each of his previous four starts. … Royals LHP Tim Collins got the final out of the eighth on his 22nd birthday .

Copyright 2011 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

KANSAS CITY, Mo. (AP) — Danny Duffy, the Kansas City Royals’ 22-year-old rookie left-hander, would like to be where Boston Red Sox lefty Jon Lester is at some point in his career.

Lester and Duffy hooked up in a pitcher’s duel for six innings Sunday. Lester limited the Royals to three hits and one run as the Red Sox won 6-1. Boston remained a half-game behind the New York Yankees in the American League East.

“Jon Lester is bona fide,” Royals manager Ned Yost said. “He’s a premier lefty in this league and he showed why.”

The Royals are hopeful Duffy can develop into one. Duffy held the Red Sox to two runs and five hits in six innings, leaving with the Royals trailing 2-0. Jason Varitek’s first triple since June 24, 2007, drove in the first Boston run in the fifth. Darnell McDonald homered in the sixth for the other run off Duffy, who was making his 17th big league start.

“Duffy pitched a great game,” Yost said. “He was on the attack. He was throwing strikes and getting ahead in the count. He hung a curve to Varitek for the triple, and he tried to go inside to McDonald and just got too much of the plate, but otherwise he didn’t make too many mistakes. He kept his pitch count in check. He was really very, very good.”

But Lester was better.

“He’s got good enough stuff to put you away and get ahead in the count, and he’s got a cutter he can use to get back in the strike zone and get back even,” said Royals first baseman Eric Hosmer, who went 0 for 3 with a walk. “He mixed it up. He threw a good game. You’ve got to tip your cap to him.”

Duffy (3-8) struck out three and walked two. He is 0-4 in four August starts.

“His stuff is good, but we finally broke through,” Red Sox manager Terry Francona said.

Duffy was much sharper than his last outing, when he gave up eight runs in three-plus innings of a loss to the New York Yankees.

“I think it was a step forward personally,” Duffy said. “It’s kind of hard to think about it that way when you lose, but personally, my efficiency was a lot better than it was against the Yankees.”

Carl Crawford also hit a solo home run for the Red Sox.

Lester (13-7) has allowed two runs and six hits in 13 innings in his past two starts to beat Kansas City and Tampa Bay. He is 5-1 with a 1.30 ERA in seven career starts against the Royals.

McDonald, who had three hits, hit his fifth home run of the season in the sixth on an 0-2 pitch from Duffy. Aaron Crow gave up a home run to Crawford, his eighth, in the seventh inning.

Ryan Lavarnway, Adrian Gonzalez and Jed Lowrie had RBIs in the eighth as the Red Sox scored three runs off Louis Coleman, one of four rookie pitchers the Royals used.

Johnny Giavotella led off the Royals seventh with a triple and scored on Mike Moustakas’ single for the only run off Lester, who was replaced by Daniel Bard after 113 pitches with two runners on base. Bard retired the next three hitters

The Royals loaded the bases on two walks and Lowrie’s error in the second, but Lester retired Alcides Escobar on a comeback to end the inning.

Lester, who no-hit the Royals on May 19, 2008, did not allow a hit until Perez’s single with two outs in the fourth.

Notes: CF Jacoby Ellsbury was out of the Boston lineup for the second straight game with a contusion in his back after being hit by a pitch Friday. It is questionable whether Ellsbury will return Monday when the Red Sox open a four-game series at Texas. “It doesn’t make a lot of sense to get him back out there too early,” Francona said. “He’s still pretty sore.” … The Royals are off Monday before playing 17 of their next 20 games on the road. … RHP Bobby Jenks, who has been on the disabled list twice this season with back tightness, is scheduled to throw 20 to 30 pitches Monday in a simulated game at the Red Sox complex in Fort Myers, Fla. … DH David Ortiz, who has missed the past seven games with bursitis in his right heel, is hitting off the tee and soft toss in the cages, but is still wearing a boot on his foot. … Red Sox LHP Erik Bedard, who starts Monday, is winless in his past eight starts against the Rangers, although he has allowed three earned runs or less in each of his previous four starts. … Royals LHP Tim Collins got the final out of the eighth on his 22nd birthday .

When: Monday through Wednesday.

Where: Progressive Field.

TV/radio: SportsTime Ohio; ESPN2 on Monday; WTAM AM/1100.

Series: Indians lead, 3-0, this season. They lead, 1,018-954, all-time.

Pitching matchups: RHP Justin Masterson (5-2, 2.52 ERA) vs. RHP Clay Buchholz (4-3, 3.42), Monday at 7:10; RHP Fausto Carmona (3-4, 4.76) vs. RHP Josh Beckett (3-1, 1.73), Tuesday at 7:05 p.m.; RHP Mitch Talbot (1-0, 1.46) vs. LHP Jon Lester (6-1, 3.68), Wednesday at 12:05 p.m.

Indians update: They are coming off three-game sweep of Cincinnati at Progressive Field. … Indians swept Red Sox at Progressive Field, April 5-7. They outscored Boston, 12-5. Reliever Rafael Perez earned two of the victories. … Talbot, on the disabled list since April 17 because of an elbow strain, is expected to be activated in time for the Wednesday start. He made his final minor-league rehab start last Thursday.

Red Sox update: The sweep in Cleveland dropped them to 0-6; they have been on a steady climb since. 1B Adrian Gonzalez (.328, 9 HR, 41 RBI entering Sunday) is an RBI machine.

Injuries: Indians – DH Travis Hafner (right oblique), OF Trevor Crowe (right shoulder), OF Grady Sizemore (right knee), RHP Alex White (middle finger), RHP Mitch Talbot (elbow) and INF Jared Goedert (abdomen) are on disabled list. Red Sox – RHP Junichi Tazawa (elbow), LHP Felix Doubront (forearm), RHP Matt Albers (right lat), RHP Bobby Jenks (right biceps), RHP Dan Wheeler (left calf), SS Marco Scutaro (left oblique), RHP John Lackey (elbow) and RHP Daisuke Matsuzaka (elbow) are on the DL.

Next for Indians: Six-game trip begins in Tampa Bay on Friday.

When: Monday through Wednesday.

Where: Progressive Field.

TV/radio: SportsTime Ohio; ESPN2 on Monday; WTAM AM/1100.

Series: Indians lead, 3-0, this season. They lead, 1,018-954, all-time.

Pitching matchups: RHP Justin Masterson (5-2, 2.52 ERA) vs. RHP Clay Buchholz (4-3, 3.42), Monday at 7:10; RHP Fausto Carmona (3-4, 4.76) vs. RHP Josh Beckett (3-1, 1.73), Tuesday at 7:05 p.m.; RHP Mitch Talbot (1-0, 1.46) vs. LHP Jon Lester (6-1, 3.68), Wednesday at 12:05 p.m.

Indians update: They are coming off three-game sweep of Cincinnati at Progressive Field. … Indians swept Red Sox at Progressive Field, April 5-7. They outscored Boston, 12-5. Reliever Rafael Perez earned two of the victories. … Talbot, on the disabled list since April 17 because of an elbow strain, is expected to be activated in time for the Wednesday start. He made his final minor-league rehab start last Thursday.

Red Sox update: The sweep in Cleveland dropped them to 0-6; they have been on a steady climb since. 1B Adrian Gonzalez (.328, 9 HR, 41 RBI entering Sunday) is an RBI machine.

Injuries: Indians – DH Travis Hafner (right oblique), OF Trevor Crowe (right shoulder), OF Grady Sizemore (right knee), RHP Alex White (middle finger), RHP Mitch Talbot (elbow) and INF Jared Goedert (abdomen) are on disabled list. Red Sox – RHP Junichi Tazawa (elbow), LHP Felix Doubront (forearm), RHP Matt Albers (right lat), RHP Bobby Jenks (right biceps), RHP Dan Wheeler (left calf), SS Marco Scutaro (left oblique), RHP John Lackey (elbow) and RHP Daisuke Matsuzaka (elbow) are on the DL.

Next for Indians: Six-game trip begins in Tampa Bay on Friday.