Paulino singled in the go-ahead run in a four-run 10th inning for his second crucial hit in an 8-4 victory over the Cardinals on Tuesday night.
"He's taken advantage of his opportunities," manager John Russell said. "He came up big for us tonight."
Doumit was injured in the first inning and Paulino entered in the second. He went 2-for-5 and drove in two runs to improve his career numbers against the Cardinals to a .316 batting average with 17 RBI.
Troy Glaus hit a three-run homer and Albert Pujols tied it with his eighth in the eighth for the Cardinals, extending his hitting streak to 12 games. Pujols, who had a day off on Monday, also walked twice and has reached base in all 40 games.
It's the majors' longest streak at the start of the season since Derek Jeter's 53-game run in 1999 for the Yankees.
Adam LaRoche added a three-run double off Ron Villone (1-1) in the 10th for the Pirates, who have won seven of eight and are one game below .500.
"I wouldn't mind ruining the save situation every night," LaRoche said. "We need those extra runs, especially against this lineup."
Nate McLouth hit a two-run homer and Paulino had a game-tying double in the seventh.
Doumit was injured on a passed ball in the first, and Russell said he has a small fracture near the tip of his thumb. The manager said Doumit would return to Pittsburgh on Wednesday to be examined, and likely would be sidelined from 10 days to three weeks depending on the severity of the break.
Marino Salas (1-0) worked around three walks, one intentional, and escaped a bases-loaded jam in a scoreless ninth to win in his major league debut. Salas, whose contract was purchased from Triple-A Indianapolis earlier in the day, got Ryan Ludwick on a high fly to shallow right to end the inning.
"That's a tough time for a guy and a lot of times there's nothing you can say," LaRoche said. "They're kind of out of their element. He looked like he was pretty calm, and I said, 'Hey, it's another game."'
Villone, who entered with a 1.26 ERA, allowed four runs, four hits and two walks in the 10th. The Cardinals have lost six of seven.
"Pathetic location, pretty much," Villone said. "If the ball was anywhere in the strike zone it was in the middle. If not, it wasn't close."
Manager Tony La Russa refused to use a reconfigured bullpen with struggling closer Jason Isringhausen in middle relief as an excuse. Isringhausen never got up in the bullpen and La Russa said two others were unavailable due to recent work.
"A couple of guys we stayed away from," La Russa said. "The guys we pitched, we could have won it anyway."
Glaus connected against Phil Dumatrait in the sixth for his second homer of the season. The drive also provided his first RBI this month and gave the Cardinals a 3-2 lead.
The Pirates came up empty with the bases loaded in the ninth against Ryan Franklin, who retired pinch-hitter Chris Gomez on an infield popup.
Glaus, who has four seasons with 37 or more homers, entered the game in a 3-for-30 slump. He singled in the fourth before his low liner barely cleared the wall in left-center in the sixth.
Kyle Lohse retired the first nine batters in order before Freddy Sanchez singled to open the fourth and McLouth followed with his 10th homer just inside the right-field foul pole. Lohse breezed through eight more hitters before the seventh.
Lohse, who looked like a mid-March free-agent steal at $4.25 million for this season, has allowed 20 earned runs over 16 innings in three starts this month.
The Cardinals have no interest in re-signing Jim Edmonds, released by the Padres, on the cheap. "I think we have enough left-handed hitting outfielders," La Russa said before the game. ... Glaus' RBI were his first since he drove in three on April 29 against the Reds. ... The Pirates began a stretch of 22 straight games against NL Central opponents. ... Pirates reliever Damaso Marte worked a perfect seventh and has retired 31 of his last 36 batters. ... Salas is the first Pirates pitcher to win in his major league debut since Paul Maholm on Aug. 30, 2005, at Milwaukee.