Updated

With Bruce Chen's 7 2/3 shutout innings leading the way, the Kansas City Royals continued their second-half surge with a 5-1 victory over the Boston Red Sox in the opener of a four-game series from Kauffman Stadium.

Chen (5-0) permitted just five hits and a walk in another masterful performance that enabled the Royals to record their 14th win in 16 games. The journeyman lefty has surrendered a mere four runs over 31 2/3 innings in five starts since rejoining the rotation in mid-July.

"I wanted to go out there and give this team a chance to win," Chen said. "I think we started with the right foot. We won the first game."

Mike Moustakas contributed a pair of hits, including a two-run single, while Billy Butler and Justin Maxwell each clubbed solo homers for Kansas City, now a scorching 16-4 since the All-Star break.

Jon Lester (10-7) overcame a rough beginning to last seven innings for Boston, allowing three runs -- one earned -- on four hits and two walks.

Stephen Drew and Jacoby Ellsbury each had two hits in the loss, only the third in 10 games for the AL East-leading Red Sox, with Drew driving in the club's lone run with a ninth-inning single.

Lester labored badly in the opening frame, throwing 40 pitches and issuing both of his two walks while catching a bad break when left fielder Jonny Gomes dropped a fly ball for a costly error that the Royals capitalized on.

After Kansas City put runners at the corners on a Lorenzo Cain double and a one-out walk to Butler, Alex Gordon hit a popup to medium-range left in which Gomes slipped and had the ball drop out of his glove as Cain tagged and scored.

Lester later gave Maxwell a free pass to extend the inning for Moustakas, who drilled a bases-loaded single to right that brought in two and stretched the lead to 3-0.

That was more than enough for Chen, who was hardly overpowering in managing just two strikeouts, but very effective. The crafty lefty yielded singles in each of the first two innings, then set down 12 of the 13 batters he faced between the third and sixth. The only Boston hitter to reach over that stretch was Dustin Pedroia, who drew a walk in the fourth.

Lester was outstanding as well after his first-inning hiccup, surrendering only a pair of singles over the remainder of his stint to keep it a 3-0 game.

"I thought he righted himself after a long first inning and I thought he did an outstanding job for the seven innings of work," Boston manager John Farrell said of Lester.

Boston made a bid to get back in it during the top of the eighth, chasing Chen on singles by Daniel Nava and Ellsbury around a couple of outs. Luke Hochevar snuffed out the threat, however, by getting Shane Victorino to pop out.

Butler's long blast to straightaway center that landed just over the glove of a leaping Ellsbury put Kansas City up by a 4-0 count in the bottom of the eighth. Three batters later, Maxwell connected off Rubby De La Rosa for the recent acquisition's second homer in six games as a Royal.

Hochevar gave up Drew's RBI single that followed a Gomes double in the ninth, but nothing else to register his second save of the season.

Game Notes

Chen's outing was his longest since tossing eight shutout innings to defeat Detroit on August 29 of last season, and he improved to 23-10 in August for his career ... Drew extended his hitting streak to 10 games and is batting .469 (15-for-32) with eight RBI over that stretch ... Nava returned to action after missing three straight games due to the birth of his daughter and went 1-for-3 ... The Royals are now 44-9 this season when scoring four or more runs.