Mike Trout and Mark Trumbo homered against Cordero to break a 3-3 tie and the Los Angeles Angels went on to defeat the Toronto Blue Jays 10-6.
J.P. Arencibia's homer in the seventh had tied the game as the Blue Jays came back from a 3-0 Angels lead provided by Alberto Callaspo's two-run homer in the fifth.
"Coco (Cordero) was the most fresh and ready to go," Farrell said. "Darren (Oliver) and Jason (Frasor) were not available because of recent usage."
Farrell added: "In those last two innings Coco and Casey (closer Janssen) were both going to be in that game even if it's a tie going into the ninth. Unfortunately, a couple of balls found their way over the middle of the plate and that's a very good hitting team."
Cordero (3-5) gave up a leadoff homer to Trout, his ninth. Albert Pujols singled with one out and Trumbo hit his 20th homer of the season.
Cordero was booed loudly as he left the game after a double by Kendrys Morales.
The Blue Jays had runners at second and third with two out in the bottom of the eighth against Ernesto Frieri but Adam Lind struck out.
The Angels scored four runs in the ninth off Jesse Chavez on a sacrifice fly by Torii Hunter, a single by Pujols, a single by Peter Bourjos off Scott Richmond, a wild pitch and a fielder's choice grounder by Morales.
Colby Rasmus hit his 15th homer of the season, a three-run blast with two out in the ninth against Jordan Walden, but the deficit was too large for the Jays to overcome.
Arencibia's 11th homer of the season came against reliever Jason Isringhausen (3-0) and meant that L.A. left-hander C.J. Wilson did not get his sixth consecutive winning decision.
Wilson hurt couldn't get an out from five batters in the two-run sixth.
He finished with three hits and five walks allowed and one of the two runs he had against him was earned.
The Blue Jays (40-39) got a second good start from left-hander Aaron Laffey, who held the Angels (44-35) to four hits and three runs, two earned, in six innings.
L.A. scored an unearned run in the first inning after Trout's lead-off double. The rookie sensation tagged up after right-fielder Rajai Davis caught a fly ball from Pujols for the second out of the inning. Davis dropped the ball on an attempted throw and Trout came around to score.
Davis started in right field for Jose Bautista, who usually plays there but was used as designated hitter for Sunday's game.
Laffey, who was making his second start for the Blue Jays, gave up his first earned runs in the fifth inning when Callaspo hit his sixth homer of the season after Howie Kendrick singled.
The Blue Jays loaded the bases with none out in the sixth on walk by Omar Vizquel, a single by Brett Lawrie of Langley, B.C., and a walk to Rasmus.
Bautista hit a grounder to second with double play potential but Kendrick let the ball get past him for an error, allowing Vizquel to score.
Rasmus mistakenly continued running and was well on the way to third, forcing Lawrie to make a dash toward home plate. He delivered a forearm to catcher John Hester in a collision at the plate.
Lawrie scrambled back to touch home for the second run. Angels' manager Mike Scioscia was thrown out in the subsequent argument with plate umpire James Hoye.
Scioscia, a former major-league catcher, had no problem with Lawrie.
"I think that's clean," he said. "I think Lawrie went after him because he's obviously trying to dislodge the ball. It's a tough play."
The umpire's decision, however, rankled Scioscia.
"In 35 years, I've never seen a catcher get bowled over at the plate, hold the ball and the runner be called safe. Never seen it," he said. "It was clear that there was a glove on him somewhere in the collision and it was clear that he didn't touch the plate because he went back to tag the plate."
Farrell had a different view.
"The throw took Hester across the plate as (Lawrie) was looking to score," said the Blue Jays manager. "It was a bang-bang play and at the same time he stepped on home plate at the moment of the collision and was safe.
"When you see the ball at second base you know there's going to be a play at the plate so you've got to brace yourself."
Lawrie, for his part, also thought it was a clean play and that he was safe.
"The throw took the catcher from his side of the batter's box across the plate and allowed him to come in front of home plate," said Lawrie. "For me as a runner I can't tell where the ball is whether it's behind me or any which way it was. I thought it was a clean play."
Hester had no problem with Lawrie lowering the boom on him.
"I was more upset about the fact he was called safe than the fact he ran me over," he said.
After Wilson walked Edwin Encarnacion to load the bases again, right-hander LaTroy Hawkins took over. Hawkins got a fly out to right field from Yunel Escobar and Torii Hunter threw out Rasmus who tried to score after the catch. Lind grounded out to second as a pinch-hitter to end the inning.
Notes: The Blue Jays wore red jerseys for Canada Day. ... Attendance at Rogers Centre was 34,853. ... Bautista, who hit 14 homers in June to set a club record for homers in any month, is the only Blue Jay who is going to the all-star game. He said is he is almost certain to take part in the home run hitting contest again this season, if the club approves. ... LHP Ricky Romero (8-2, 4.94 earned-run average) will open the four-game series against the Kansas City Royals on Monday night against left-hander Everett Teaford (0-1, 5.06 ERA).