BOSTON (AP) - Jon Lester's performance was symbolic of his team's first half - a mediocre outing.

Lester, the projected ace of the staff at the start of the season, lasted just 4 1-3 innings and allowed five runs as the Boston Red Sox lost 7-3 to the New York Yankees Sunday night in the finale of a four-game series.

"I've got to keep grinding and working. I can't give up," said Lester, who dropped to 5-6 with a 4.49 ERA. "I just have to go and relax and not think about my first half."

Boston lost three of four in the set to their rivals and fell back to .500 (43-43), dropping into last-place tie with Toronto, 9½ games behind the AL East-leading Yankees.

"I'd rather not," a dejected looking Red Sox manager Bobby Valentine said when asked to talk about the weekend series. "I wanted to win as many as we lost. It's just disappointing."

A sign of how weak the Red Sox were in the first half: Only three AL teams - Minnesota, Kansas City and Seattle - are currently below .500.

The Red Sox entered the All-Star break with two-thirds of their starting outfield sidelined with injuries, but they're hoping to get left fielder Carl Crawford and center fielder Jacoby Ellsbury back soon.

Crawford has missed the entire season with left elbow and wrist injuries. Ellsbury was sidelined in mid April with a right shoulder injury.

"We've got to get through it, I guess," slugger David Ortiz said, sitting at his locker in a quiet room. "I think people understand our situation with the injuries. It can't get worse. Well, I guess it can."

Valentine said Ellsbury's "pretty sure he's going to be with us in Tampa" for the first series after the break.

Ivan Nova struck out 10, Andruw Jones hit his fourth homer in three games and the surging Yankees went into the break with a major league-best 52-33 mark. They hold the biggest division lead in baseball at seven games over Baltimore.

Nova (10-3) allowed two runs and six hits in six innings. Jones provided a cushion with a two-run homer in the seventh that gave New York a 7-2 lead.

Lester, who won at least 15 games in each of the last four seasons, left with one out in the fifth after giving up five runs and nine hits. Until Sunday, the lefty had rebounded from early-season troubles and posted a 3.86 ERA in 13 starts.

The Yankees scored in the first inning in all four games in the series, taking a 2-0 lead in the finale. The first three batters all hit safely - singles by Derek Jeter and Curtis Granderson and an RBI double by Mark Teixeira. Granderson scored when Nick Swisher grounded into a forceout.

The Red Sox got an unearned run in the bottom of the inning when Jeter dropped a routine popup by Cody Ross with two outs. The shortstop's misplay scored Pedro Ciriaco, who had singled and stolen second.

New York made it 3-1 in the second on a double by Jayson Nix, a passed ball by Jarrod Saltalamacchia and a sacrifice fly by Chris Stewart. Boston came back again with a run in the third on Ciriaco's single and Ortiz's double.

The Yankees drove Lester from the game in the fifth, scoring twice for a 5-2 lead. Teixeira started the rally with a single and scored on a triple by Alex Rodriguez. Jones then singled in Rodriguez.

Nova won five consecutive starts before going 0-1 in his next three. He would have gotten out of a first-inning jam had Jeter held on to the soft popup near second base. The righty even pumped his fist and started walking off the mound but stopped as the ball bounced out of Jeter's glove.

Then Nova struck out the side in the second before escaping trouble in the third when the Red Sox scored a run and loaded the bases with one out. But Saltalamacchia struck out for the fifth time in seven at-bats and Ryan Sweeney grounded out.

Nova fanned three of his last four batters and at least one in each of his six innings.

Jones' homer was his 11th of the season and the Yankees' 134th, most in the majors. They're on a pace for a club-record 255. The 1997 Seattle Mariners hold the major league record with 264.

NOTES: Robinson Cano extended his hitting streak to 15 games with a double in the ninth, tying Jeter for the longest on the Yankees this year. ... Ortiz's double was his 373rd with the Red Sox, tying Jim Rice for sixth in club history. ... Nova had lost his last road start, ending a streak of 16 starts without a loss away from home. ... Jeter scored his 1,816th run in the first, tying Boston's Carl Yastrzemski for 16th on the all-time list. ... Red Sox 1B Adrian Gonzalez left the game in the third because of illness. He struck out in his only at-bat, ending his career-best hitting streak at 18 games. ... The Red Sox will honor Jason Varitek before their night game July 21 against the Toronto Blue Jays. The catcher retired in February after 15 seasons with the team. ... Ceremonial first pitches were thrown by Ted Williams' daughter Claudia (to Rice) and Babe Ruth's granddaughter Linda Ruth Tosetti (to Ortiz).