This was supposed to be the weekend the New York Yankees tightened the AL East race in front of their home fans. Instead, the Toronto Blue Jays are burying them.

A four-game sweep and an eighth straight win at Yankee Stadium are on the line Sunday, and R.A. Dickey hasn't lost since before the All-Star break or to the Yankees in more than two years.

The Blue Jays (82-60) won 9-5 and 10-7 in Saturday's doubleheader to extend their division lead to a season-high 4 1/2 games, get to a season-best 22 games over .500 for the first time since 1993, and send the Yankees (77-64) to five straight losses.

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Toronto had never won more than six straight in New York, but it came at a cost with Troy Tulowitzki breaking his left scapula in Game 1 during a second-inning collision with center fielder Kevin Pillar.

"It's not good news, we'll probably have a little better idea in a few days how long they might think (he's out)," manager John Gibbons told MLB's official website. "Kind of a freak thing, it's unfortunate, but it means a couple of the other guys have a chance here to step up."

Toronto has scored 30 runs and hit .323 with 10 home runs in the first three games of the series. Ben Revere went 6 for 12 Saturday and is batting .427 with 22 runs scored in his last 21 games, while Jose Bautista is 6 for 13 in the series.

New York, three games up on Texas for the top wild card, is in danger of matching a season-worst six-game skid from May 17-24, and it hasn't dropped six straight at home since May 11-20, 2011. The Yankees' most crippling skid might be a four-gamer as part of a 4-11 season against Toronto.

"We need to worry about ourselves," manager Joe Girardi said. "We need to right this. We need to pitch better."

They haven't been bad offensively in the series with 17 runs scored, but it hasn't been nearly enough to keep pace. Brett Gardner homered three times in nine at-bats Saturday and is 6 for 12 with eight RBIs in the series.

Dickey (10-10, 4.01 ERA) is 7-0 with a 2.68 ERA in 11 starts dating to July 18. Toronto lost that game, but it's won 10 straight Dickey starts since. There was a rough patch in there where he allowed 16 runs in 22 2-3 innings over his last four starts of August, but the right-hander has given up two runs in 15 innings over his last two.

"I really felt great with my knuckleball. It was firm. There were a lot of swings and misses," Dickey said after not earning the decision in Tuesday's 5-1 win in Boston. "I felt very consistent with it in the strike zone."

Since losing at Yankee Stadium on Aug. 21, 2013, Dickey is 4-0 with a 1.14 ERA in seven starts in the series.

Chris Young (1 for 13), Brian McCann (6 for 25), Carlos Beltran (6 for 31) and Chase Headley (3 for 15) are all hitting .200 or worse against the 40-year-old.

Masahiro Tanaka was on that level in his last start against the Blue Jays, tossing a five-hitter in a 4-1 victory Aug. 15 in Toronto. The right-hander is 4-2 with a 2.65 ERA in six career starts in the series.

Ryan Goins (0 for 9), Josh Donaldson (1 for 10), Dioner Navarro (2 for 16) and Bautista (3 for 17) have all struggled, but Edwin Encarnacion is 7 for 14 with a home run.

Tanaka (11-6, 3.57) was also in strong form in Tuesday's 2-1 home loss to Baltimore, allowing a run and six hits with a season-high 10 strikeouts in eight innings. He avoided the decision and is 3-1 with a 2.97 ERA in his last five starts beginning with the win in Toronto.