The Atlanta Falcons' 17-6 upset of the Los Angeles Rams Sunday was not a fluke.

They shut down the Rams' running game, harassed quarterback Joe Namath into hurrying most of his passes and played mistake-free football on offense.

That is precisely the game plan in mind for this Sunday's encounter with the Washington Redskins at RFK Stadium.

He doesn't expect to catch the Redskins by surprise, especially after Washington showing in its loss to the New York Giants.

"George Allen doesn't lose two games in a row very often," Bennett said yesterday. "You know he's going to have them laying for us. The Redskins are always a tough team to plan for since they do such a good job of taking away what you do best."

Personnelwise, the Falcons are not all that different last year. It's their attitude that has changed. They now beleive in themselves.

Bennett, who spent the last four seasons as an assistant with the Rams, was forced to make one major change when his starting quarterback. Steve Bartkowski, injured his knee and underwent surgery last week.

That left Scott Hunter as the No. 1 Atlanta quarterback.

Many observes, Bennett included, were skeptical of Hunter. But Hunter, with Bennett calling the plays, turned in a workmanlike job by completing 10 to 17 passes for 121 yards.

Hunter was signed by the Falcons as a free agent prior to the start of last season. He had led Green Bay to the NFL's Central Division championship in 1972. In 1974 he was traded to Buffalo, but played in only one game. He was out of football all of 1975. . .

The Atlanta attack is basically a conservative one. Against Los Angeles, Haskel Stanback ran the ball 18 times for 73 yards and Monroe Eley 21 times for 60 yards.

Stanback, the NFC's leading rusher in the preseason, could be a 1,000-yard rusher, according to Bennett.

Eley played four seasons in Canada before joining the Falcons in 1975. He spent last season on injured reserve.

The Falcons have two rookies on their offensive line - No. 1 draft pick, 6-foot-7, 270-pound Warren Bryant, from Kentucky, at right tackle and No. 2 pick, 6-4, 247-pound R. C. Thielemann, from Arkansas, at right guard.

Defensively, the Falcons are wide open and daring. They blitzed freely against the Rams and even when they weren't blitzing, their pass rush, led by end Claude Humphrey, caused problems. Namath was sacked three times for 33 yards in losses.

Humphrey said namath's lack of mobility helped Atlanta's pass rush.

"It's always easier when you don't have to chase a moving target," Humphrey said.

When it comes to mobility, the Redskins' Bill Kilmer is considered to be in the same class with Namath.

Atlanta limited Los Angeles to 59 yards rushing and took the ball from the Rams on fumbles three times.

That's pretty impressive for a team that finished 25th in the NFL in rushing defense last season.