PITTSBURGH -- Ike Davis didn't complain when the Pittsburgh Pirates told him they were going to eat into his playing time by experimenting with Pedro Alvarez at first base. Call it the byproduct of spending four-plus seasons with the New York Mets.

"You kind of get immune to stuff after a while," Davis said. "Kind of my career has been starting, not starting, so I'm used to it."

Davis is simply happy to be in a pennant race at the moment. He provided a needed jolt in a pinch-hit appearance Tuesday night, connecting for a tiebreaking three-run homer off St. Louis reliever Seth Maness in the eighth inning of a potentially costly 5-2 victory.

Pirates star Andrew McCutchen left in the fifth inning because of discomfort in his left ribs. Recently on the disabled list because of a rib problem, the center fielder ran into the wall earlier in the game.

"Today caught up to him in a couple of different ways," Pirates manager Clint Hurdle said of the reigning National League MVP. "Tonight got to be a point where we didn't think we needed to push any farther than he did."

It's uncertain whether McCutchen will be available Wednesday, but Pittsburgh survived for a few innings without the four-time All-Star thanks in large part to Davis. The Pirates squandered six brilliant innings by Gerrit Cole when Tony Watson (9-1) couldn't get out of a two-on, no-out jam in the seventh that allowed the Cardinals to tie the game.

No matter. Watson recovered to get out of the jam and retired the side in the eighth, and the Pirates wasted little time getting to Maness in the bottom of the inning. Gaby Sanchez singled with one out, and Starling Marte followed with his second hit of the night.

The Cardinals decided to stick with Maness (5-3) after a brief conference. It didn't work.

Davis shook off a called strike that appeared to be below his knees and delivered a towering shot to right-center that landed in the last row of seats.

"We got into a good count, had a couple real nice pitches and left one up in the middle," St. Louis manager Mike Matheny said. "That's not going to turn out well."

Josh Harrison also homered for the Pirates, and Mark Melancon worked the ninth for his 23rd save.

Jon Jay and Randal Grichuk each drove in a run for the Cardinals. Lance Lynn gave up two runs over six innings in a bid for his fourth consecutive win.

Pittsburgh, trying desperately to stay in the hunt for a wild-card slot, appeared in danger of a second straight disheartening defeat after a brilliant effort by Cole vanished.

The 23-year-old overwhelmed the Cardinals for long stretches in his second start since returning from the disabled list after being sidelined by right lat soreness. St. Louis didn't get a hit until a two-out double just inside the first-base bag by Kolten Wong in the sixth. Cole responded by fanning Matt Holliday for his ninth strikeout of the game.

Hurdle decided to send Cole back out for the seventh with a 2-0 lead even though he had thrown 102 pitches. Trouble soon followed.

Matt Adams led off with a double, and Jhonny Peralta followed with a single. Watson, who has slipped a bit over the past month following a dazzling first half, came on but couldn't quell the rally.

Adams scored on a sacrifice fly by Jay, and Grichuk -- called up earlier in the day after outfielder Shane Robinson was placed on the disabled list with a shoulder injury -- slapped a single up the middle to tie the game.

TRAINER'S ROOM

Cardinals: St. Louis put Robinson on the 15-day disabled list with a partially dislocated left shoulder. He hurt himself while trying to steal second late in a 3-2 win over the Pirates on Monday. He went back to St. Louis for an MRI on Tuesday. Matheny said there is no timetable for Robinson's return.

Pirates: Alvarez exited in the seventh inning with left foot discomfort. Making his sixth start at first base following serious throwing issues while playing at third base, Alvarez went 0-for-3 and handled every defensive chance cleanly before giving way to Sanchez. Alvarez will be re-evalulated Wednesday.

UP NEXT

Cardinals: Adam Wainwright (15-8, 2.52 ERA) goes for his major league-leading 16th win Wednesday. Wainwright's nine road victories are tied for second in the majors, and his 1.74 road ERA is tops among all starters.

Pirates: Jeff Locke (5-3, 3.69 ERA) is 3-1 with a 3.78 ERA in eight starts at PNC Park this season. The left-hander allowed two runs in six innings in an 8-3 victory over Milwaukee on Friday.