Sunday, however, he will be pitching in St. Louis as a Padre. Williams said he isn't feeling any pressure.
"Without being overconfident, even when we were down 2-0 (to the Cardinals), we were loose and confident," he said. "We play our best ball when our backs are to the wall.
"The bottom line is, if I pitch well, we keep going. It's been that way the last five or six starts. It's fun. We've played so long to get to this point. May as well keep going."
The Padres are hoping Williams is the pitcher who won his last five starts of the regular season with a 2.73 ERA, including a 7-5 victory over his old team Sept. 26 at the new Busch Stadium. Williams was 8-1 in his last 10 starts.
Plus, he seems to bring out the best in the Padres. They were 17-7 in his 24 starts. And while other Padres pitchers have struggled with the lack of run support, Williams has been getting more than six runs a game -- the sixth-highest figure in the National League.
Williams will be matched against Chris Carpenter, who won the series opener Tuesday in San Diego, on Sunday.
Despite winning 3-1 Saturday the Padres stranded 14 baserunners, including nine in scoring position -- seven of which got into position with less than two outs (including two runners who reached third with none out). Russell Branyan's two-run double is the only hit the Padres have with runners in scoring position in 25 at-bats against the Cardinals.
Said Mike Piazza: "We like to strand the population of a small village on the bases. It's our trademark. It's fun doing things the hard way. We were anxious with runners on. It was obvious. We were kind of laughing that it was a typical win for us."
After the Cardinals had lost Game 3 of the National League Division Series, 3-1, to the San Diego Padres on Saturday, manager Tony La Russa nominated ace right-hander Chris Carpenter to pitch Sunday's fourth game even though it meant that Carpenter could not start the first game of the next round if they get that far.
On the other hand, if he didn't use Carpenter and saved him for a possible fifth game, the Padres could gain some momentum in this series, which would return to San Diego on Monday. La Russa doesn't want to go back to San Diego and really didn't want to have to play Sunday,
"With Chris, we're going to give it our best shot," he said. "It's a game we'd hope not to have to play, but you try to wrap it up as soon as you can. They've got to win."
Carpenter beat San Diego easily, 5-1, in the first game, getting 2 2/3 innings of spotless relief.
The Cardinals' bullpen, composed mostly of youngsters now that closer Jason Isringhausen is on the disabled list, has pitched 11 scoreless innings in the series, allowing only seven hits and striking out 13.
But the Cardinals, after a strong first game, haven't hit. There is concern mostly about third baseman Scott Rolen, who is 1-for-11 and fanned in a key first-inning spot Saturday after center fielder Jim Edmonds was walked intentionally to get to him.