Monroe's three-run homer off Scott Proctor with two outs in the ninth lifted the Tigers to a 5-3 victory Wednesday night, preventing Detroit's dwindling lead in the AL Central from getting sliced to 3½ games.
"Let's be honest, that was a big win," Monroe said.
Chien-Ming Wang tied Toronto's Roy Halladay and the White Sox's Jon Garland for the major-league lead with his 16th win in the day game, combining on a four-hitter in a 2-0 victory. And New York had rallied from a two-run deficit in the nightcap.
Seeking his first major-league save, Proctor (5-4) walked Brandon Inge with one out. After fouling off a pair of 3-2 pitches with two outs, Curtis Granderson took ball four. Monroe turned on the next pitch, a weak slider, and drove it to left-center for his 23rd homer. It was his 10th homer from the seventh inning on with the lead or deficit two runs or less.
"We've been doing it all year," Tigers manager Jim Leyland said. "We have a good team. We're not a fluke."
Detroit won for the seventh time this year when trailing after eight innings, and the home run made Marilyn Monroe very happy. Craig's mother, who lives in Texarkana, Texas, was visiting New York for the first time, and he was disappointed he had gone 0-for-4 in the opener.
"Just to see the excitement on her face," he said.
As the ball sailed high over him, Derek Jeter didn't even turn around at shortstop. He just dropped his head between his legs and swiped the infield dirt with his hands.
"I need to attack guys better, do what I've been doing all year. It's just embarrassing," said Proctor, who had thrown one pitch in the opener. "You just can't walk guys."
Farnsworth felt a twinge in his back between games, a problem he's had a few times this year, and had a wrap around his waist after the nightcap.
"I thought I could have gone out there today, but Joe thought otherwise," he said.
Torre spoke to Farnsworth just before the second game began.
"I said, 'How you doing?' He says, 'OK.' That wasn't good enough for me," Torre said.
Torre refused to use Rivera, who threw 14 pitches in the opener.
"I have to look at the big picture," Torre said. "This game isn't an October game. That's when you throw the rules out the window. We've got to take as good a care of him as we can."
Still, New York boosted its AL East lead to eight games over second-place Boston, its largest division margin since August 2004.
Detroit, which has lost eight of 12, has a 4½-game lead over second-place Chicago, down from a 10-game division advantage on Aug. 8.
Wilfredo Ledezma made his second start of the season and extended his scoreless streak to 22 innings before the sixth. He left with two on, and Jeter pulled a two-run double down the left-field line against Fernando Rodney and then scored on a roller to third by Alex Rodriguez.
A-Rod was booed several times as he went 0-for-7 in the doubleheader, leaving him with one hit in 24 at-bats. After Granderson caught up with his drive to deep right-center in the fifth inning of the opener, A-Rod bounced his helmet off the infield dirt just past first base.
The opener drew a turnstile attendance of 18,167 out of 52,585 tickets sold.