Pirates starting pitcher Victor Santos sits in the Pirates dugout during the third inning of Tuesday's game in St. Louis. Santos was the losing pitcher in the Cardinals 6-3 win.

ST. LOUIS — In his 20th game with the St. Louis Cardinals, Juan Encarnacion finally made some impact.

Encarnacion homered, tripled and doubled, driving in four runs to help the Cardinals beat the Pittsburgh Pirates 6-3 Tuesday night. He had entered the game with one RBI.

"Every time you're doing something to help the team it's always good, especially in the situation I've been in the whole time I've been here," Encarnacion said. "I felt pretty good tonight and I'll try to carry that to tomorrow."

Jeff Suppan, a 16-game winner last year, won for the first time in four starts this season. Suppawn (1-2) allowed three unearned runs and four hits in seven innings on a cold 47-degree night.

Jason Isringhausen worked the ninth for his sixth save in seven chances, completing a four-hitter.

Hector Luna added three hits, raising his average to .438 in limited duty, as the Cardinals won for the fifth time in six games.

Pittsburgh has lost six in a row, getting outscored 30-9, and is an NL-worst 5-17. The Pirates also lost six in a row at the season's start and have dropped 11 of 12 on the road.

Victor Santos (1-4) gave up five runs and eight hits in five innings.

"It's real tough," Santos said. "It's just no fun."

Encarnacion had 16 homers and 76 RBI last year for Florida, then signed a $15 million, three-year contract with St. Louis. His only RBI before Tuesday came on a groundout and he had one extra-base hit and a .203 average in 69 at-bats.

Encarnacion hit an RBI double in a two-run first. With Pittsburgh leading 3-2 in the third, he followed Jim Edmonds' two-out walk with a homer to left for a 4-3 lead.

"That shows you what Juan can do," Cardinals manager Tony La Russa said. "People are all the same, when you have a little success, you're more confident and it gives you a chance to have more success. I'm sure he'll feel better about it."

Encarnacion added a run-scoring triple in the fifth, when right fielder Jeromy Burnitz missed on an attempted sliding catch and the ball rolled to the wall. Going for the cycle, Encarnacion bunted foul trying for a hit in the seventh, then grounded sharply into a double play against Roberto Hernandez.

In his previous outing, Suppan gave up eight runs and lasted only two innings. In this one, all of the Pirates' runs came after a catcher's interference call on Gary Bennett in the third, and Suppan retired 13 of his last 14 batters. He is 7-2 against the Pirates, a team he played for in 2003.

"A lot was different," Suppan said. "I was able to make some pitches that I wasn't able to do the previous game. Basically, my plan was to leave what was in the past, in the past, and really focus on what I had to do."