Jon Lester and Jason Varitek played big roles in the Red Sox win Sunday afternoon. (AP)

KANSAS CITY — Jon Lester turned in his second straight stellar outing, Sunday afternoon, this time leading the Red Sox to a series-ending, 6-1 win over the Royals at Kauffman Stadium.

The Sox lefty held the Royals to one run over six innings, lowering his ERA to 3.16. In his last two starts, Lester has allowed two runs over 13 innings.

Leading the offense were solo homers by Darnell McDonald (3-for-5) and Carl Crawford, with the first Sox run coming via Jason Varitek’s first triple in more than four years. The Sox were able to seal the deal via a three-run eighth, highlighted by Ryan Lavarnway’s RBI double that hit off the very top of the left field wall.

Here is what went right (and wrong) in the Red Sox’ 77th win of the season:

WHAT WENT RIGHT

- Daniel Bard came on with nobody out, and two on in the seventh and preserved Lester’s win. The righty first fanned Alcides Escobar, and then got an Alex Gordon fly out,  followed by Melky Cabrera’s ground out to shortstop keeping the Red Sox lead at 3-1.

- For the first time since June 24, 2007, Varitek hit a triple. This time around the fifth-inning line-drive into the right-center field gap proved important, giving the Red Sox a 1-0 lead by driving in Jed Lowrie with two outs.

- McDonald, who had manned the No. 2 spot in the Red Sox’ lineup just two other games this season, made the most of being moved up in the batting order. In his second at-bat he ripped a single, and then went deep over the left-center field wall for his fifth homer of the season in the sixth, with all of the home runs coming against left-handed pitching. The outfielder punctuated his day with an eighth-inning single for his first three-hit game since Sept. 5 of last season. He now has four three-hit games for his career.

- Carl Crawford took an 1-1 pitch from Aaron Crow in the seventh inning well over the right field fence (416 feet) for his eighth homer of the season, giving the Sox a 3-0 lead. It was just Crawford’s second home run since June 9, a stretch that included 40 games and 150 at-bats. His previous home run came Aug. 1 against Cleveland at Fenway Park.

- The Red Sox closed things out with the three-run eighth in which Adrian Gonzalez (single), Jed Lowrie (sacrifice fly) and Lavarnway (double) all came away with RBI.

WHAT WENT WRONG

- A two-out error by Lowrie on a Salvador Perez grounder extended Lester’s inning by 11 pitches, although the lefty did manage to get out of a bases loaded jam thanks to Alcides Escobar’s grounder bak to the pitcher.

- The Red Sox experienced two bouts of poor baserunning. The first came in the first inning when Marco Scutaro got hung up between first and second after Gonzalez swung and missed at a third strike for the inning’s second out.

- Lester ran into trouble he couldn’t get out of in the seventh inning, having to leave the game after failing to get an out while allowing an RBI single from Mike Moustakas. The Sox starter began the seventh having thrown 10o pitches. He exited the game with runners on first and second and nobody out, giving way to Bard.