It is a confidence born of his unmatched consistency and success over the last three years.
"I can't think of a pitcher I'd rather have out there."
Game 1 of the World Series?
Why would he think any differently?
"On any given day I feel I can handle any club," Stewart said after throwing a five-hit shutout at the San Francisco Giants Saturday night.
"I knew if I had my stuff it would be a tough game for the Giants.
"I'm real proud of the fact that when people talk about a guy who can come in and win in a pressure situation, my name is generally mentioned."
"Stew is the best in the league and maybe in baseball at giving his club a chance to win," the A's manager said. "I mean, he's risen to the occasion so many times."
Forget the Cy Young Award Stewart has never won.
Forget the possibility that he has deserved more recognition.
Stewart has a 4-1 record in postseason play, including a 3-0 mark this year, permitting just five earned runs in 25 innings. He has a 24-9 record in 1989, including the postseason, and a 62-34 regular-season record over the last three years.
Saturday, amid the caldron of this Bay Area Series, Stewart walked one, struck out six and was threatened only in the ninth.
Will Clark and Kevin Mitchell opened that inning with consecutive singles, but Stewart struck out Matt Williams and Ernest Riles and got Candy Maldonado on a grounder to third.
He threw 139 pitches and showed no evidence of the sore and tired shoulder he complained about in September.
"I had a job to do and went out and did it," Stewart said.
"I beat Roger Clemens, 1-0, last year and still think that was the best game I've ever pitched, but if I had to grade myself tonight I'd give it an A.
"In this situation I couldn't have asked for much better. It was as good as I've pitched this year.
"I don't feel that I've ever done a better job of staying on top of an entire lineup. I pride myself on doing different things to every hitter every at-bat.
"That's what pitching is all about, and that's what I think I did tonight."
A former pitcher named Roger Craig, the Giants' manager, appreciated the effort.
"Stewart went after us just like the scouting report said he would," Craig said. "He got ahead with his fastball, then went to the forkball.
"We thought he might tire, but he maintained his velocity for the entire game. We just couldn't make contact. You have to give him credit."
Stewart completed only eight of 36 starts during the regular season.
The A's, with Dennis Eckersley the bottom line in a deep bullpen, seldom ask the members of their rotation to finish what they start.
La Russa went to the mound after the singles by Clark and Mitchell and trusted Stewart when he said that he still felt strong, still felt in control.
"We very rarely let our starters throw more than 125 pitches," La Russa said, "but one benefit of protecting them all year is that you can let them go to the well in the postseason.
"I wasn't sentimental about Stew getting the shutout. I just felt that he still had good stuff and mechanics.
"And I still didn't see any (Giant) runs on the scoreboard."
Stewart said the six days between starts helped his stamina and velocity.
"Physically," he said, "I don't feel like I threw 139 pitches, but mentally I know I had to work. The Giants have an explosive club. I watched a couple of their playoff games on television in which the (Chicago) Cubs seemed to have them down. Then bam. Robby Thompson or Will Clark or Kevin Mitchell did something and they were back in it or on top. I was aware of the hitters I had to work on. I couldn't have been better prepared."
Stewart generally struggles in the early innings, then takes charge. He said that once he got out of the first inning Saturday night, "I knew the middle innings would be mine like they always are."
It was a year ago today that Stewart left Game 1 of the 1988 World Series against the Dodgers with a 4-3 lead after eight innings. Eckersley then yielded the dramatic home run to Kirk Gibson in the ninth, depriving Stewart and the A's of their victory--and, perhaps, momentum.
Was Stewart wrestling with those demons Saturday night? Did he carry the memory?
"Last year had nothing to do with this," Stewart said. "I've been in tough games all year and I treated this as just another game.
"That's not to say I don't realize the importance of it. Any time you win a Series opener it's a first step. They have to play catch-up now, and that's what we had in mind. If you can keep 'em trying to catch up, pretty soon it's over."
Stewart will next pitch Game 5, if it's needed, and would be available to work Game 7 in relief.
The Cy Young votes have already been cast. Stewart accepts the fact that Bret Saberhagen of the Kansas City Royals will probably win it. Is the recognition there now?
"In this league there's no award for consistency," Stewart said. "For the last 3 1/2 years the numbers say there's been no better pitcher than Dave Stewart.
"The Cy Young is awarded on a year-to-year basis, and this year Saberhagen had the best year and should win it.
"If my recognition isn't there after 62 wins over the last three years, then people haven't been watching. I think I've been the most consistent pitcher in the American League, maybe in baseball, in that time, and I think the credit is there now."
If not, the Giants are probably among those who think that it should be.