While Baltimore fans spent more time cheering the Orioles than the Colts, the Washington Redskins opened their preseason game schedule tonight by getting a big boost from their miniback tandem of Clarence Harmon and Buddy Hardeman.

The two runners put on a third quarter show that dazzled the Colt defense, helped the Redskins to a 13-3 victory and eased at least some of the apprehension about Washington's backfield problems.

Coach Jack Pardee has never doubted that either Harmon or Hardeman could be successful as a starter and they backed up his confidence with powerful performances that could help offset the possible loss of holdout fullback John Riggins.

Halfbacks Ike Forte and Bobby Hammond also ran well, and fullback Don Testerman had a decent second quarter. His showing was especially curcial for Washington, which must produce a strong backup fullback from the current roster to help out Harmon -- barring Riggins' return -- or be forced to go out and get one in a trade.

Harmon gained 29 of his 47 yards in the third quarter while Hardeman, starting this season in place of Benny Malone, added 18 of his 38. Hardeman also had one 10-yard pass reception, while Harmon had a seven-yarder, during Washington's only touchdown drive of the night.

Pardee said he was relieved the way the backs ran. "They performed the way I thought they would. We want to interchange them and use everybody. I was really happy that they had super averages (Harmon 5.2 on nine attempts, Hardeman 4.8 on eight)." The Redskins finished with 204 yards rushing.

All of their heroics probably were lost on the 31,636 Colt fans in attendance. They came equipped with radios to listen to the Orioles versus Yankees game from New York. Whenever something important happened in Yankee Stadium, a huge cheer would go up. The biggest blast came when the Orioles won the game, and the resulting roar had the Colt bench looking around, wondering what was going on.

The Colt's really didn't give rooters much to yell about. Other than some fine midgame passing from quarterback Bert Jones, who is on the comeback trail from shoulder miseries, Baltimore was lackluster on offense and outmanned on defense, especially by an aggressive Washington offensive line that controlled the game all night.

Baltimore's only score came on a 19-yard field goal by ex-Maryland kicker Steve Mike-Mayer late in the second period. That offset a 26-yard field goal early in the second period by Ed Delgado, Washington's backup kicker.

Mark Moseley, the Redskins' No. 1 kicker, later added a marvelous 52-yarder that cleared the crossbar with plenty of room to spare.

Harmon scored the Washington touchdown on a two-yard run in the third period.

Quarterback Joe Theismann, who played the first and third quarters, cmpleted five of 10 passes for 22 yards. Backup Kim McQuilken, who played during the second quarter, had a crisp showing, completing five of six attempts for 35 yards. Newcomer Mike Kruczek made his Redskin debut and was two of three for eight yards with one interception.

Taking the ball at their 20, the Redskins embarked on an 80-yard, 14-play march that ate up more than six minutes of the clock on this hot, muggy night.

Harmon, who has become the club's quickest back through extensive weightlifting, raced around right end for eight yards.

Hardeman, who was used mostly as a kick returner and third-down pass receiving specialist last year, sprinted for six yards, followed by a nine-yard Harmon sweep of left end.

Hardeman picked up a first down on a three-yard plunge and Theismann found Harmon over the middle for six more. On Hardeman's turn, he zipped off right guard for 10 yards and a first down at the Colt 38.

Two plays after a 10-yard completion to Hardeman, a Theismann pass to Hardeman was overthrown and the running back slammed against the covering over the Orioles' dugout. He left the game temporarily and was replaced by Forte, who ripped off gains of three and seven yards to move the ball to the 13.

Harmon tried the middle for three and followed that with his most impressive run of the night. He started around left end and got into a footrace with Colt linebacker Ed Simonini, who tried to cut him off at the corner. Last year, he might have been able to, but not now. Harmon turned upfield and was knocked out at the two.

On the next down, he followed the blocks of guard Fred Dean (playing for the injured Jeff Williams) and Hardeman for an easy touchdown and a 10-3 Redskin lead with 3:27 left in the third period.

The first Redskin field goal came after McQuilken engineered a nice-looking 50-yard march that was stopped by a Washington mistake inside the 10.

The club began the drive at the 41 with its second offensive unit going against the Colts' No. 1 defense. A nine-yard McQuilken pass to Forte advanced the Redskins across the 50 and two completions to Testerman netted a first down at the 28.

McQuilken's quick toss to rookie Ricky Claitt accounted for six yards and Testerman plunged for a first down at the 17. Two plays later tight end Don Warren broke free inside the five. McQuilken laid the ball in his hands but he bobbled it while being tackled by Colt rookie Derrick Hatchett. When he hit the ground, the officials ruled he did not have possession.

A third-down pass to Testerman fell two yards short of a first down and Delgado came on to kick the field goal for a 3-0 Redskin lead.

Baltimore scored with time running out in the first half. Jones completed five passes in the drive, including a bullet toss of 13 yards to rookie Mike Butler that gave the Colts a first down at the two with five seconds left and no timeouts. New Coach Mike McCormack opted for the field goal and Mike-Mayer easily booted the 19-yarder for a 3-3 tie.

Monk, the club's No. 1 draft choice, caught one pass, which he fumbled trying to turn into a longer gain. Defensive end Mat Mendenhall, the No. 2 selection, started in place of the injured Coy Bacon.