Long before he threw the deciding touchdown pass against the New York Giants Sunday, Joe Montana executed the "play" that allowed him and the San Francisco 49ers to win the game.

It happened just before the opening kickoff. It's the latest chapter in coach Bill Walsh's offensive philosophy: quarterback platooning.Montana faked a handoff to Steve Young, then dropped back to the sidelines and pretended to be a dutiful backup quarterback for the first half.

On the inside Montana was burning up. But on the outside he remained Joe Cool. There is no doubt he was bothered when Walsh told him on Saturday that Young would be the starter.

"Does this elbow look swollen?" Montana asked Saturday night, holding up his right arm. It was bruised, but not swollen. "It feels fine. I could play."

Montana admitted his disappointment, observing that if he knew he was not going to start, then he would have preferred to give his arm treatment and rest Friday rather than throw in practice.

But Montana did not lose his composure, as Jay Schroeder did when he was displaced by Doug Williams as Washington's starting quarterback this year. Montana played the game, saying he understood why Walsh named Young the starter.

And that is why Joe Cool was back on the field in the second half and able to throw that spectacular, 78-yard touchdown pass to Jerry Rice with only 42 seconds left as the 49ers pulled out a 20-17 victory.

Platooning quarterbacks is an unusual practice in the NFL. You can substitute pass rushers or receivers or nickel linebackers, but not quarterbacks.

However, Walsh is noted as one of the game's most innovative offensive coaches. His passing game is state-of-the-art. So hold the snickers and criticism, especially while the team is 2-0.

But why does Walsh want to tinker with this system and why does he believe it will work for him when it has failed for so many others in recent years?

First, by using two quarterbacks Walsh puts pressure on opposing defenses who have to study as if they will play two different offenses.

Second, although neither Young nor Montana warmly embraces this philosophy, they are rare individuals who mute their personal opinions rather than disrupt the team ... for now.

Strategically, Walsh is tantalized by the difference between his two quarterbacks - Young the quick-footed left-hander and Montana the quick-triggered right-hander.

Consider that the Giants mauled Montana and the 49ers in the last two meetings of the non-strike teams. Walsh wanted to get the Giants off balance this time.

Walsh, an amateur boxer in his younger days, pestered the Giants in the first half by jabbing them with his lefty. Young completed 11 of 18 passes for 115 yards and ran five times for 48 yards. If it weren't for his two fumbles, Young might have collected 13 or 17 points. But at the half, the fight was even on points, 10-10.

Then it was Montana's turn. He completed 10 of 18 for 148 yards and finally landed that knockout shot, the 78-yard TD to Rice.

But will this platooning continue to work? That may depend on whether Montana and Young can continue to accept it gracefully. Their perspective is different from Walsh's.

"Joe didn't practice much this last week and we thought Steve would be a good dimension for us," Walsh said of his decision to open with Young. "Then we thought Joe would have good accountability when he went into the game as to what we thought we could do."

But Young felt he was just getting into the flow of things when he was taken out. And Montana felt that he could have started and established a consistent attack throughout the game. They each played a half and left the game feeling half-empty.

"I was surprised a little because I felt we were settled in and we would move the ball and put some points on the board," Young said when asked his thoughts about being taken out after the first half.

"Whenever you don't start you are disappointed," Montana said. "If I was healthy enough to play the second half, I obviously was physically able to start. But it was the coach's decision and I had a feeling what would happen when I didn't take a lot of snaps this week."

And what does Montana think about a two-quarterback philosophy?

"That's not for me to worry about right now," he said.

Oh, and by the way, coach, who will be the starting pitcher Sunday against Atlanta?

"Joe Montana," Walsh said quickly.

With Young ready in the bullpen, of course.