Joba Chamberlain takes a breather after allowing a run in the first inning of Tuesday's game against Toronto. (Kathy Willens/Associated Press)

The Blue Jays got to phenom Joba Chamberlain early, then broke the game open with a six-run seventh inning off the weakened Yankees bullpen to cruise to a 9-3 win Tuesday night in New York.

Toronto's rout spoiled the much-hyped starting debut of Chamberlain, 22, who earned a bump to the rotation after beginning his major-league career as a dominant reliever.

Rod Barajas and David Eckstein smacked two-run doubles off separate Yankee relievers in the seventh, while Roy Halladay pitched a solid six innings for the Jays (32-28), who won for the 15th time in 21 games to improve to 4-3 on their nine-game road trip.

The Jays have scored 66 runs in their last 12 outings, posting a 9-3 record in the process.

"I felt like for the most part we were pretty good when we had to be," said Halladay, who won his fourth straight decision to improve to 7-5. "It was one of those games where you were grinding all the time."

Uneven debut

Chamberlain, who burst onto the scene late last season with a 0.38 earned-run average and 34 strikeouts in 24 innings to help the Yankees earn the AL wild card, didn't make it to his team-imposed limit of 65-70 pitches on Tuesday.

Burning more than half his allowance in a bumpy first inning that featured three walks, a balk, a pass ball and a Toronto run. But the flamethrower worked a perfect second inning before being yanked with one out in the third. For the night, Chamberlain allowed two runs — one earned — on one hit while walking four and striking out three over 62 pitches.

"I wanted to get my team a lot deeper into the game and it wasn't very good," said Chamberlain, after making his first start since July 2007, when he made his last of 15 starts as a minor leaguer. "That's what it comes down to. I've got to be better, that's for sure."

Chamberlain's uneven big-league debut won't faze the Yankees (28-30), who are committed to a long-term plan of converting him into a full-fledged starter. The team has been steadily increasing his workload over the last few weeks after deciding to move him out of the bullpen, where in 23 innings this season he posted a 2.28 ERA and 30 strikeouts.

"It was the first step, that's all," said Yankees co-chairman Hank Steinbrenner, who watched the game in his office at the Yankees' facility in Tampa, Fla. "Again, he's 22. This was the first step. We're looking at a 10-year or more career.

"Tonight was a creation of the media. If this had been a first start for any other pitcher on any other team, it wouldn't have been such a big deal."

While Chamberlain offered a glimpse into the Yankees' future, shortstop Derek Jeter brought a reminder of the past when he singled in the ninth inning off Jason Frasor. The hit was the 2,415th of Jeter's career, tying him with Mickey Mantle for third on the Yankees all-time list, behind Lou Gehrig and Babe Ruth.

Rough start

Perhaps overly charged up making his starting debut in front of a hopeful crowd of 53,629, Chamberlain struggled from the get-go despite touching 101 miles per hour on the Yankee Stadium radar gun. After walking leadoff batter Shannon Stewart, he fanned Marco Scutaro, but promptly committed a balk to move Stewart into scoring position. Stewart got to third after a Chamberlain delivery to Alex Rios went past catcher Jose Molina, then scored on Rios's groundout.

Toronto threatened to do more damage as a Scott Rolen single preceded consecutive walks, earning Chamberlain a visit from pitching coach Dave Eiland. But after the breather, Chamberlain flashed the kind of stuff that's made him a highly touted prospect, blowing a 98 mile per hour fastball past Barajas to end the inning.

The Yankees did their best in the bottom of the first to support their young starter. Johnny Damon led off with a triple to the gap in right-centre, and later scored on a Hideki Matsui single. Jason Giambi then beat Toronto's defensive shift by slapping one through the hole at shortstop to score Alex Rodriguez, who had reached base when Halladay accidentally plunked him.

Chamberlain retired the side in order in the second inning, but with his pitch limit looming early in the third, got the hook from manager Joe Girardi after a one-out walk to Rios.

A frustrated Chamberlain blew off steam by yelling into his glove as he strode off the mound. The often unforgiving Bronx crowd, which included Chamberlain's father, Harlan, who is in a wheelchair, sent the fan favourite off with a hearty ovation.

"I was mad at myself," said the younger Chamberlain. "You know you've only got so many pitches and I didn't do a very good job of conserving those pitches."

Double trouble

Dan Geise — the first of five Yankee relievers on the night — saw his season debut get off to a rocky start.

While Giese (0-1) faced his first batter, Rios stole second, advanced to third on Molina's errant throw, then scored on a Rolen groundout as the Jays pulled even at 2-2.

Toronto took the lead in the next inning as Barajas led off with a double and scored on Eckstein's sacrifice fly two batters later.

Geise departed after the sixth, and the Jays went to work loading the bases off Jose Veras and Edwar Ramirez. The latter walked Lyle Overbay on four straight pitches, plating an insurance run, then coughed up a two-run double down the left-field line to Barajas.

LaTroy Hawkins — fresh off a suspension for throwing at an opposing batter — came in to try to stop the bleeding, but Eckstein promptly lashed his own two-run double down the right-field line. Brad Wilkerson then tagged and scored on Scutaro's lineout to left, making it 9-2.

New York got one back in the bottom of the seventh off reliever Brian Tallet, who walked his first two opponents before ceding an RBI fielder's choice to Bobby Abreu.

But that's as close as the Yankees would get, as Jesse Carlson and Jason Frasor worked a scoreless eighth and ninth, respectively.