R.A. Dickey's knuckleball finally danced like it did last year when he was the best pitcher in the National League.

Dickey baffled the New York Yankees for seven innings and Colby Rasmus and Rajai Davis homered as the Toronto Blue Jays won the opener of a three-game series 2-0 on Tuesday.

"What you saw tonight is what I saw last year for 25 starts," said catcher Josh Thole who accompanied the Cy Young Award winner to Toronto in an off-season trade with the Mets. "It was consistently that every night."

Dickey (13-12) struggled in the first two innings then faced the minimum number of batters for the next five innings. He struck out eight in holding the Yankees to four hits and two walks to win his fourth decision in a row.

'It was probably the latest action I've had on [my knuckleball] here in particular. So it's nice to continue to grow. These are important games for me in particular. We're going to be competing next year so it's important to get it right now'- Jays pitcher R.A. Dickey

"It was probably the latest action I've had on it here in particular," Dickey said. "So it's nice to continue to grow. These are important games for me in particular. We're going to be competing next year so it's important to get it right now."

Rasmus hit his 21st homer of the season — and third in three games since returning from the disabled list — in the fourth inning against left-hander Andy Pettitte (10-10).

Davis hit his sixth of the season against right-hander Shawn Kelley in the seventh.

The Yankees (79-72), who entered Tuesday 2.5 games out of an American League wild-card spot, have lost four in a row. The Blue Jays (69-81) have won only twice in their first seven games of a nine-game home stand.

Sergio Santos took over from Dickey in the eighth. Casey Janssen pitched the ninth for his 31st save of the season.

Pettitte lost for the first time since Aug. 5 as he allowed six hits, two walks and one run while striking out five in 6 2/3 innings. He had three wins and four no decisions in his previous seven starts.

"It's frustrating," Pettitte said. "We're playing terrible and it's not good. It's a bad time to be doing that. If we pitch we got to score some runs. If we score some runs, we've got to pitch. It seems like we haven't been doing a lot of mixing and matching together. Dickey pitched a good game. His knuckleball, he threw it well."

Dickey left the bases loaded in the first when he struck out Mark Reynolds. He left two more runners stranded in the second, and struck out the side in the third before being helped by a fourth-inning double play.

'Stay the course'

"I didn't get discouraged the first two innings," Dickey said. "I was throwing good knuckleballs. I thought I had a couple of pitches there 3-2 and ended up being balls but outside of that it was moving pretty drastically tonight. Even in the first two innings, I knew I had a pretty good one. I just needed to stay the course with it."

The Blue Jays took a 1-0 lead with one out in the fourth when Rasmus homered to right on a 2-2 hanger. The centre-fielder came off the disabled list on Sept. 13 after not playing since Aug. 11 because of an oblique strain.

"I made a terrible mistake to Rasmus and that was the ball game," Pettitte said. "He got me deep into an at-bat. I kept trying to bounce a cutter off the top of the plate see if I could try and get him to swing. Bad thought process."

Kelley replaced Pettitte with two out in the seventh and Davis homered to left on a 1-0 pitch to extend the lead to 2-0.

The way Dickey's knuckleball was working, that was all the Blue Jays needed. He even tried two sidearm pitches.

"The knuckleball stayed hard for most of the night, it was moving all over the place," Thole said. "In the 'pen it was moving more than I've seen since I've been here. It was definitely a mental grind for seven innings tonight.

"He got stronger as he went on I think. That was the difference. You could see it. His velocity kind of jumped up I think in the third inning, he was throwing the harder consistently and it was all over."