"That shutdown inning to maintain some momentum, once again, a little bit elusive here tonight," Blue Jays manager John Farrell said.
It was clear early on that Jenkins, who was making his second Major League start, didn't have his best stuff.
The right-hander allowed three consecutive two-out hits in the first inning, the third of which was a two-run double by Nick Swisher that put New York ahead, 2-0.
Jenkins' struggles continued into the second. After allowing a leadoff single to Raul Ibanez, he walked back-to-back batters to load the bases for Derek Jeter. The Yankees' shortstop hit into a double play but cashed one run to give New York a 3-0 lead.
Jenkins lasted 3 2/3 innings, allowing three runs on four hits while walking three.
This performance was in contrast to Jenkins' first big league start, when the righty -- who had made 10 appearances out of Toronto's bullpen -- allowed the Rays one run on two hits over five innings. Farrell intended to build up Jenkins' pitch count on Friday after the rookie threw just 66 pitches his first start, but the rookie was pulled after 67 this time around.
"I thought Chad went out tonight and had decent stuff, was down in the zone from the get-go, more so than his last outing," Farrell said. "But this team came out tonight and swung the bat very well against us."
Jenkins felt he was overthrowing his sinker and by the time he started feeling good, he had already put his team in a hole. He said his arm felt strong but his pitches were coming out flat.
"It was subpar, for the most part," Jenkins said. "I didn't throw a lot of strikes, was kind of all over the place."
Farrell turned to six relievers after Jenkins, and like the 24-year-old, the crop had trouble silencing the potent Yankees offense.
Brett Cecil, who relieved Jenkins, retired six of the eight batters he faced, including the last two by way of strikeout, before turning the ball over to Jason Frasor with two on and two outs.
Frasor worked a 1-2 count against Russell Martin before the Canadian catcher hit a three-run homer to left field to give New York a commanding 6-1 lead. Two of the runs were charged to Cecil.
"It's definitely a big blow -- you go from a two-run lead to a five-run lead," Martin said of his career-high 20th home run of the season. "It definitely hurts the other team and helps us. At that point, it felt like we were in control."
The veteran Frasor then allowed a walk and back-to-back singles -- the second by Ichiro Suzuki, which plated one -- before exiting without a retiring a batter and Toronto trailing, 7-1.
Three of the next four Blue Jays relievers allowed runs, including Bobby Korecky, who surrendered a two-run homer to Eric Chavez in the ninth in his Blue Jays debut. Korecky is the 53rd player Toronto has used this season, tying a franchise record set in 1999 and matched in 2011.
Lefty Aaron Loup was the only Blue Jays pitcher to keep the Yankees off the board.
As much as the pitching struggled, Toronto made some key mistakes on the bases, too.
The first came from Brett Lawrie, who led off the first inning with a double to left field. Swisher fielded a grounder by Colby Rasmus at first base and fired the ball to Jeter at second to get Lawrie, who had wandered too far off the bag.
More mistakes on the bases cost the Blue Jays in the following inning. Yunel Escobar started off the frame with a double and later advanced to third on a wild pitch, but he didn't stay there long. After Yankees starter Hiroki Kuroda struck out Kelly Johnson, Martin threw to third and got Escobar for the second out of the inning.
"The aggressiveness, there is a difference between being alert and aware, and yet the overaggressiveness took guys out of their position," Farrell said.
Toronto put the next three runners on to load the bases, but Kuroda struck out Rasmus looking and escaped the threat.
The Blue Jays wasted another chance in the fourth, stranding Rajai Davis at second with no outs, before Rasmus put Toronto on the board by crushing a solo homer, his career-high-tying 23rd of the season, in the fifth.
Kuroda lasted 5 1/3 innings, allowing two runs on 10 hits to improve to 15-11.
"We answered his pitches with some hard-hit balls, [but] we took ourselves out of a couple of those run-scoring situations," Farrell said.
Adam Lind clubbed a two-run homer in the seventh, his 11th of the year, Davis matched a career high with four hits and J.P. Arencibia extended his hitting streak to a season-high six games.
Toronto, which is tied for fifth place in the American League East, has lost 16 of its past 24 games against the Yankees and 13 of 18 overall.