BOSTON (AP) -- Jon Lester is proving he's Boston's ace again.
Lester pitched eight dominant innings, and the AL East-leading Red Sox dealt the New York Yankees' wild-card hopes another blow with a 5-1 win on Saturday.
The 29-year old left-hander is 6-3 since mid-July with a 2.52 ERA in 12 starts after a rough stretch midway through the season.
"What he's done since the All Star break has been consistent with how he's started the season," Red Sox manager John Farrell said. "A well above-average pitcher, a front-line starter and that's what Jon Lester is."
Lester (14-8) was solid from the start, mixing a sharp cutter with a well-spotted, mid-90s fastball. He allowed one run and three hits, striking out five and walking two for his fourth win in six starts.
Midway through the season, he went 0-4 in six starts with a 7.20 ERA.
"I knew after what I went through at the middle of the year that it's just a matter of time and things will take care of itself," he said. "I think anytime you take someone that's had some success, your confidence is high. When you struggle, that kind of varies from certain starts."
Mike Napoli, Jonny Gomes and Shane Victorino each had two hits as the surging Red Sox won for the 16th time in 19 games, and beat the Yankees for the fifth time in six meetings in just over a week.
Napoli, in his first season with the Red Sox, has seen the best of Lester from the opposite side.
"I remember facing him when he had his changeup, it's tough because he'd throw that cutter in on your hands and a changeup strike when he's just pounding you inside all the time," he said. "He's been doing great. You can see he's confident out there. He's just getting the ball and throwing."
The Yankees lost their second straight after a three-game winning streak and fell 21/2 games behind Tampa Bay for the AL's second wild-card spot. The Rays play at Minnesota on Saturday night.
"You have to find a way to get it done is the bottom line," New York manager Joe Girardi said of facing Lester. "He's been throwing the ball well. He threw it well against us last time and he did it again today, but you've still got to find a way."
Boston entered the day with an 81/2-game lead over second-place Tampa Bay.
The Red Sox (91-59) improved to a season-high 32 games over .500, their best mark since the final day of their World Series championship season in 2004.
Franklin Morales worked a perfect ninth.
For the second time in week, Boston goes for a sweep against New York. Last weekend, the Red Sox won the initial three of a four-game set at Yankee Stadium but lost the finale.
The Red Sox built a 5-1 lead against CC Sabathia (13-13) after five innings.
"I felt like I was behind everybody and got into some tough counts," Sabathia said. "With a team like they have, when you get behind and in a hitter's count, you're going to give up some hard-hit balls."
ATHLETICS 1, RANGERS 0
ARLINGTON, Texas -- Bartolo Colon scattered seven hits over eight impressive innings for the AL West-leading Oakland Athletics, who stretched their division lead over Texas to 51/2 games with a 1-0 victory over the Rangers and Yu Darvish on Saturday.
The A's won for the seventh time in eight games, and clinched the key division series by beating Texas twice in less than 24 hours.
Colon (16-6) struck out seven and lowered what is already his career-best ERA to 2.73.
Darvish (12-9) struck out 10 over seven innings in his fourth 1-0 loss of the season. The right-hander from Japan has lost his last four starts, the last two by 1-0 scores, and is winless his last six.
Even though Darvish struck out the side in the first, Josh Donaldson drew a one-out walk and scored on a two-out double by Brandon Moss into the right field corner.
BLUE JAYS 4, ORIOLES 3
TORONTO -- Colby Rasmus hit a two-run home run, Jeremy Jefress won for the first time in more than two years and the Jays handed the slumping Orioles their fifth loss in seven games.
Rasmus erased Baltimore's 3-2 lead with a drive off the facing of the second deck against Chris Tillman (16-6) in the seventh inning. For Rasmus, it was his 20th homer of the season and second in two days.
Jeffress (1-0) pitched one scoreless inning of relief to win for the first time since April 5, 2011, when he beat the Chicago White Sox while pitching for Kansas City.
Tillman allowed four runs and six hits in eight innings to lose for the first time since Aug. 19.
MARLINS 3, METS 0, 1ST GAME
NEW YORK -- Donovan Solano got some payback after he was hit by two pitches, launching a home run and making two terrific defensive plays that sent Henderson Alvarez and the Marlins past the Mets in the opener of a doubleheader.
Logan Morrison drove in two runs, one on a line drive off the right wrist of Frank Francisco that knocked the oft-injured reliever out of the game. Alvarez (4-4) pitched four-hit ball over seven innings for his second win against the Mets this year.
Carlos Torres (3-5) hit Solano with pitches in his first two plate appearances. Torres struck out a career-high eight in six innings and gave up only three hits.
PIRATES 2, CUBS 1
PITTSBURGH -- Gerrit Cole pitched seven strong innings and got home run help from Marlon Byrd and Jose Tabata, leading the Pittsburgh Pirates past the Chicago Cubs Saturday night.
The Pirates have won five of six. They began the day one game behind St. Louis for the NL Central lead.
Cole (8-7) gave up one run and five hits. The rookie struck out seven and walked three.
Byrd hit a solo home run off James Russell (1-6) in the seventh to put Pittsburgh ahead 2-1.
It was Byrd's 23rd home run of the season and second in 17 games since being acquired Aug. 27 from the New York Mets in a trade. He is hitting .323 for the Pirates.
BRAVES 2, PADRES 1
ATLANTA -- Kris Medlen allowed four hits over 71/3 scoreless innings to win his fourth straight start, leading the Atlanta Braves to a 2-1 win over the San Diego Padres on Saturday night.
The Braves led 2-0 before Chase Headley hit a ninth-inning homer off closer Craig Kimbrel, who then pitched around a two-out walk to Ronny Cedeno for his career-best 47th save -- the most in the majors.
Freddie Freeman had three hits, including a sixth-inning homer off Robbie Erlin (2-3), to help the Braves earn their first win of the season over the Padres. San Diego won the first four games of the season series.
The NL East-leading Braves began the night 10 games ahead of second-place Washington.
Medlen (14-12) has enjoyed a strong resurgence after a slow start. He went 1-6 over the first two months of the season.
MARINERS 4, CARDINALS 1
ST. LOUIS -- Rookie James Paxton gave up two hits in six shutout innings and the Seattle Mariners ended a five-game losing streak, beating St. Louis 4-1 Saturday night and dropping the Cardinals into a first-place tie in the NL Central.
St. Louis and Pittsburgh share the division lead once again. The Pirates topped the Cubs 2-1.
The Cardinals mustered only three hits, including Matt Carpenter's league-leading 50th double in the eighth. He later scored on a wild pitch by Charlie Furbush.
Franklin Gutierrez hit a two-run double in the fifth inning that ended St. Louis rookie Michael Wacha's scoreless streak at 23 2-3 innings. Kendrys Morales hit his 22nd homer in eighth off Tyler Lyons to make it 3-0.
The St. Louis hitters have been struggling all week, and they never got going at all against the 24-year-old Paxton (2-0), who limited them to a pair of singles.
The first was by Wacha (3-1) in the third when Paxton came off the bag to field a tapper and then slipped and fell, losing his grip.
INDIANS 8, WHITE SOX 1
CHICAGO -- Ubaldo Jimenez pitched 81/3 strong innings and Asdrubal Cabrera and Lonnie Chisenhall homered to lead Cleveland to an 8-1 victory over the Chicago White Sox on Saturday night that helped the Indians keep pace in the American League wild-card race.
Cabrera hit a two-run homer and Lonnie Chisenhall added a three-run shot in a five-run fourth inning that powered the Indians to their 11th straight win against Chicago and third in a row overall to improve to 80-68.
Texas, at 81-66, holds one wild-card spot and Tampa Bay at 80-66 has the other.
Jimenez (12-9) scattered eight hits and struck out eight to win his third straight start.
Chicago starter Andre Rienzo (2-2) lasted just four innings, allowing five runs on seven hits and four walks.