Billy Kilmer silenced his booing critics yesterday with three touchdown passes as the Washington Redskins, with a lot of help from its defense, cruised past the St. Louis Cardinals, 24-14 before 55,031 at RFK Stadium.

Frank Grant, Jean Fuggett and John Riggins all were on the receiving end of Kilmer's touchdown's tosses. Riggins' 53-yard touchdown's with a short pass over the middle with 6:04 left to play left the Redskins with a 2-1 record, and the Cardinals at 1-2.

The Redskin defense snuffed out the usually highly flammable Cardinal offense, with the exception of Jim Hart's seven-yard touchdown pass to tight end J.V. Cain early in the fourth quarter and a final meaningless touchdown by Wayne Morris with 28 seconds remaining.

Cain's touchdown had cut the Redskin lead to 14-7, but Joe Lavender's clutch interception killed the next Cardinal threat, and Riggins' spectacular pass-run followed on the Redskins' next possession to sew up the win for Washington.

For added measure, defensive end Ron McDole intercepted a Hart pass to set up Mark Moseley's 41-yard field goal with 2:33 left.

George Allen introduced his special teams before the opening kickoff, and the suicide squad immediately came up with a big play when Eddie Brown returned Cardinal punter Terry Joyce's first kick 14 yards to give the Redskins excellent field position at the Cardinal 48.

The Redskins, who had not scored a touchdown in the first quarter of six preseason and two regular season games this year, changed all of that on their opening offensive series.

With that wonderful field position, and a little help from Cardinal linebacker Mark Arneson, Kilmer drove the Redskins 48 yards in nine plays, hitting wide receiver Frank Grant with a 12-yard touchdown pass with 8:03 left in the opening period.

On third and six from the Cardinal 33, Kilmer sent fullback John Riggins out of the backfield on a delay and tried to hit him with a quick pass, Arneson was clinging to Riggins' back, and though the pass fell incomplete, Arneson was called for interference. That gave the Redskins a first down at the St. Louis 24.

Two straight running plays by Calvin Hill and a third by Riggins left the Redskins with a fourth-and-inches situation at the Cardinal 15. Allen elected to gamble and go for the first down, which Mike Thomas made when he squeezed through the right side for a three-yard gain to the 12.

On first down, Kilmer put Grant in the slot on the left side and had him run a basic post pattern over the middle. Grant made a spiffy catch with Cardinal Cornerback Perry Smith on him, for the score.

Mark Moseley's extra point gave the Redskins a 7-0 lead which held up through halftime. The Redskins had excellent field position three more times in the half, but could not capitalize.

The only other scoring threat came midway through the second period when Moseley missed a 47-yard field goal attempt wide right.

The Redskin defense, meanwhile, was making life miserable for a Cardinal team that came into the game ranked third on offense in the National Football Conference.

The Cardinals managed only two first downs in the first period and six in the half, and had a meager 101 yards total offense in the first half.

They were constantly pinned deep in their own territory by punter Mike Bragg's seeing eye kicks. On four of their seven offensive series, the Cardinals had to start from their 10-, 5-, 10- and 2-yard lines.

Their best field position of the game came after Moseley's missed field goal, but they never penetrated Redskin territory in the first half.

The Redskins had a scare late in the first half, however, when cornerback Pat Fisher left the game after making jarring head-on tackle of Steve Jones just after the two-minute warning. He was able to get up and walk off the field under his own power.

Fishcher suffered a mild concussion, but was back briefly at the start of the third quarter.

Kilmer got the Redskins moving quickly in the third period with a 25-yard pass to tight end Jean Fugett to the Cardinal 42. But Thomas fumbled after an eight-yard gain on the next play and Arneson recovered at the Cardinal 33.

The Cardinals finally moved into Redskin territory on their first possession of the second half with a 15-yard pass from Jim Hart to Mel Gray and a 12-yard run down the right sideline by Terry Metcalf, pushing the ball to the Washington 31.

But the Cardinals could get no closer than the 29 , and Jim Bakken's 45-yard field goal attempt, was blocked by Diron Talbert.

From the Redskin 29, Kilmer launched his team on a 72-yard scoring drive that ended with Fugett's 27-yard touchdown catch with 6:10 left in the third period.

Four times in the 10-play drive, Kilmer completed third-down passes. The first two went to Thomas and the third to Fugett for a 16-yard gain to the Cardinal 27.

Three plays later, on third and eight from the 27, Fugett worked his way open on a post pattern and was alone at the five where Kilmer hit him on the numbers. Fugett survived a goal-line pop by Cardinal safety Mike Sensibaugh, and held onto the football for the touchdown.

Moseley's extra point stretched the Redskin lead to 14-0.

The Cardinals finally got moving on the first possession of the fourth-quarter, mostly because of Metcalf and his quick feet. He caught a dumpoff pass over the middle for a 31-yard gain to the Redskin 47, then two plays later ran 20 yards more to the Redskin eight.

A personnal foul call on Ken Houston for a late hit on Metcalf gave the Cardinals a first and goal at the Redskin three.Washington pushed the Cardinals back to the nine on second down when Gerard Williams tackled Jones for a six-yard loss.

Two plays later, on third and seven, Hart faked a handoff into the line to Wayne Morris and threw a tight end J.V. Cain in the left corner of the end zone. Cain made a leaping one-handed catch for the touchdown, completing an eight-play, 63-yard drive.

Bakken's extra point cut the Redskins lead to 14-7 with 10:53 left in the game.

The Cardinals stopped the Redskins cold on their next series, and got excellent field position when Metcalf returned Bragg's punt 12 yards to the Cardinal 47.

St. Louis drove had a second and one at the Washington 32, but the game turned black in the Redskins' favor when Joe Lavender intercepted Hart's pass intended for Ike Harris on the left sideline.

The Redskins took over at their own 14, and quickly got out of the hole when Thomas ran 22 yards up the middle for a first down at the Redskin 36.

Two plays later, the Redskins put the game away for good when Kilmer hit Riggins, who was coming across the middle. Riggins found daylight, broke tackles by Sensibaugh and Lee Nelson at the Cardinal 40, and raced to the end zone with a 53-yard touchdown.

Moseley's extra point gave the Redskins a 21-7 lead with 6:04 left to play.

Ron McDole got the ball back for the Redskin when he intercepted a pass intended for Metcalf in the flat with a spectacular one-handed, juggling catch, McDole returned the ball 15 yards to the Cardinal 32.

The Redskins could not get a first down, but Moseley kicked a 41-yard line-drive field goal for a 24-7 Redskins lead with 2:33 left to play.