The crowds at Texas Stadium, even during playoff games, are normally reserved, reacting to modest gains with modest applause and spectacular plays with corporate restraint. But something odd happened in Irving Sunday.

Sixty-five thousand, forty-two Dallas fans decided the best way to inspire their team was not with a nod, but an ovation--a standing one, at that.

It all happened in the third quarter after Dennis Thurman had intercepted a pass thrown by Tampa Bay quarterback Doug Williams. The Cowboys were leading, 10-6, at that point, but they looked as flat as polished slate. The officials called for a television timeout.

A timeout usually means timeout for a beer in living rooms from Elko to Englewood, but it is a kind of black hole in space at the stadium--the crowd murmurs, the vendors vend and the players stand frozen.

This time it was different in Irving. Slowly and without obvious motivation--like a flash storm approaching--the Dallas fans stood and cheered, louder and louder, so that when the commercials ended, viewers returning from the kitchen must have thought the kids had been fiddling with the dial or doctoring the brew.

Drew Pearson even made like a Redskin, whipping his arms around in the air to increase the volume.

From there, after Williams' 49-yard touchdown pass to Gordon Jones, the Cowboys looked better and better, and won, 30-17.

"It was real gratifying to hear them come alive like that," quarterback Danny White told the Associated Press. "It was inspiring; there was no way we were going to lose that game."

The Cowboys' last two regular season games, losses to the Philadelphia Eagles and the Minnesota Vikings, did little to inspire the city. Seventy-two hours before the game, there were 15,000 tickets remaining, causing a local television blackout. The remaining tickets disappeared quickly after the announcement.

The ovation, and the cheering that continued until the end of the game, was as helpful as it was surprising.

Afterwards, Coach Tom Landry called the fans the game's "most valuable players."

Tampa Bay tackle Charley Hannah might have voted the officials the least valuable players after they called him for an illegal block against linebacker Mike Hegman at a crucial point in the fourth quarter. After the penalty was called, nullifying a first-down run, Hannah kicked the official's hankerchief and earned an unsportsmanlike conduct call for his trouble. On the next play, third-string rookie safety Monty Hunter intercepted Williams' pass into the flat and returned it 19 yards for a touchdown to put the Cowboys ahead for good at 23-17.

Although he said the penalties did not cost the Buccaneers the game, Coach John McKay contended game films revealed Hannah hit Hegman squarely on the shoulder--only after the initial contact did Hegman have his back to Hannah.

With the erratic Tampa Bay game behind them, the Cowboys will need every advantage when they face the Green Bay Packers at Texas Stadium Sunday. Green Bay routed the St. Louis Cardinals, 41-16, the day before to reach the second round of the Super Bowl tournament.

Although White's injured right thumb will improve by next week, the injury report for the Cowboys could be better. Defensive tackle John Dutton is doubtful with a badly bruised thigh; running back Ron Springs, with a bruised knee, is questionable, and Dextor Clinkscale, Tony Hill, Ed Jones and Pearson are listed as probable, nursing minor injuries.

Green Bay has history, as well as health, on its side. The Packers have an 8-3 record against the Cowboys, including NFL championship victories over Dallas in 1966 and 1967.

In the 1960s, the Cowboys were expansion upstarts; the Packers, coached by Vince Lombardi, were the Establishment, as indomitable as the phone company. Now the roles are reversed.

Sunday's game will be played not on the frozen Lambeau Field turf, but in Texas Stadium. Packers Coach Bart Starr, who must have noticed the crowd's rumblings in Irving, was asked if the Cowboys had a decisive home field advantage.

"I think most people would tend to go that way, but you still have to take advantage of a so-called edge," Starr said. "We'll be ready to play.