ST. LOUIS (AP) _ As usual, the Rams-49ers game was decided by brilliant quarterbacking and a receiver wearing No. 80.

With one big difference _ the Rams prevailed, beating San Francisco 42-20 on Sunday to break a 17-game losing streak against the 49ers and become the NFL's only unbeaten team.

``I've been waiting all my career to watch my quarterback take a knee to beat this team,'' said defensive tackle D'Marco Farr, a sixth-year Ram who had been 0-10 against the 49ers.

The heroes for St. Louis were Kurt Warner, who threw five touchdown passes, and Isaac Bruce, who caught four, fitting for a team that had been repeatedly beaten by Joe Montana and Steve Young throwing to Jerry Rice, a more renowned ``80'' than the oft-injured Ram.

St. Louis also got help from Tony Horne, who put the game away with a 97-yard kickoff return late in the third quarter.

The Rams (4-0) are perhaps the most surprising NFL team so far this year. They have had nine straight losing seasons, the longest current streak. Dallas and New England, the only other undefeated teams going into Sunday's games, both lost.

Rams coach Dick Vermeil had said playing San Francisco was ``just another game.'' But after the victory he bear-hugged owner Georgia Frontiere at midfield and blew a few kisses to the crowd.

``We've finally caught up with the best team in our division,'' Vermeil said.

Yes, the Niners were playing with Jeff Garcia instead of Young, who missed his second straight game with a concussion. But that hadn't stopped San Francisco in the past: Elvis Grbac beat the Rams here for the 49ers and so did Jim Druckenmiller.

Garcia wasn't to blame, though. The Rams simply got another outstanding performance from Warner, the former Arena League quarterback who had three touchdown passes in each of his first three games this season.

He threw TD passes of 13, 5 and 42 yards to Bruce on St. Louis' first three possessions as the Rams took a 21-3 lead. Warner was 10-of-10 for 177 yards before Lance Schulters intercepted a pass at midfield.

Late in the first half, Warner found Jeff Robinson, a former defensive lineman converted to tight end, for a 22-yard score that made it 28-10. Three of Robinson's four catches in a seven-year career were in the game.

Warner added a 43-yard touchdown pass to Bruce in the fourth quarter, finishing 20-of-23 for 323 yards. Bruce finished with five receptions for 134 yards.

Warner, who has 14 touchdown passes this season after taking over for the injured Trent Green in the third exhibition game, made one of his few mistakes toward the end of the first half.

He dropped back to pass from his own 9 and fumbled when he was hit by a blitzing Tim McDonald. Junior Bryant fell on the ball in the end zone for a San Francisco touchdown, making it 28-17 at halftime.

``Warner was terrific,'' San Francisco coach Steve Mariucci said. ``They've got a good quarterback making good decisions and taking care of the football.''

The Niners (3-2) cut it to 28-20 on Wade Richey's 43-yard field goal late in the third quarter. But Tony Horne took the kickoff, darted through a huge hole on the left side and easily outran Richey and Nate McMillian for the score.

Then Bruce beat Darnell Walker, whom he victimized all game, for the final score.

The last time the Rams beat the 49ers was Nov. 25, 1990, when they were the Los Angeles Rams and Montana was the quarterback for the 10-0 49ers. Only Young and Rice of the current Niners played in that game and none of the Rams are left.

The emotion of St. Louis' victory extended to the 49ers.

Midway through Vermeil's post-game news conference general manager Bill Walsh came in, hugged the coach and offered his congratulations.

``You're going all the way, Dick'' Walsh told him.

``Don't say that,'' replied Vermeil, one of Walsh's many proteges.

The game marked the return to St. Louis of Lawrence Phillips, who was the Rams' first draft choice in 1996 but cut in 1997. He was roundly booed when he came on the field for the first time and booed again when he scored San Francisco's first touchdown on a 2-yard run.

Garcia finished 22-of-36 for 233 yards but was intercepted on each of his last three possessions.

But at the end, it was all about the streak, even from the San Francisco side.

``When you play these guys, you constantly hear about it,'' Mariucci said. ``I tried to make mention to the team that the streak had nothing to do with this game. They had to play the game from scratch.''

So, at least one good thing happened to the 49ers. Next time, they won't have to worry about the streak.

Notes Warner's 14 touchdown passes in four games are two more than the Rams had all of last year. ... Rice caught a pass for the 198th straight game, an NFL record. ... Warner's five touchdown passes marked the eighth time a Rams quarterback has done that. ... Warner had thrown 84 passes without an interception and had 15 straight completions before Lance Schulters picked off a pass in the second quarter . ... A holding call on cornerback Dexter McCleon in the first quarter was the first penalty this season on the Rams' defense. ...Phillips had four carries for 9 yards and two catches for 11 yards and two kickoff returns for 55 yards. ... San Francisco defensive lineman Marvin Washington is out of the year with a ruptured quadriceps tendon. ... Rams running back Marshall Faulk injured a hip in the first quarter. He returned later but had just 6 yards on seven carries.