Neil Lomax threw for 354 yards and Roy Green caught third-quarter touchdown passes of 70 and 45 yards to lead the St. Louis Cardinals to a 31-20 upset of the Dallas Cowboys today. It was only the second time in 13 games the Cardinals had beaten Dallas in Texas Stadium and the first time since 1977.

The Cardinals (3-3) moved within a game of the lead in the National Football Conference's Eastern Division. Dallas (4-2) dropped into a first-place tie with the Redskins, whom they will play at Washington next Sunday.

"We know that to compete with Dallas and Washington and the other great teams, we have to beat them sometimes," said Lomax, who completed 19 of 29 passes.

"We haven't done that for six or seven years. This team worked hard during the offseason for games like this. This just shows what we can do when I get some time to throw."

St. Louis not only moved the ball all day, gaining 477 yards in total offense, but frustrated the Cowboys to the point that Coach Tom Landry replaced quarterback Gary Hogeboom in the third period with Danny White. Hogeboom, who was booed often, completed 13 of 28 passes for 143 yards and was intercepted twice by the Cardinals, who were missing their starting cornerbacks.

"There is not much you can say when you get whipped," Landry said. "No excuses. We got knocked back all day.

"It was just a matter of time. I put Danny White in there to try to get something to happen."

Asked if White would start next week, Landry said, "I don't know yet. I don't know about that."

The Cardinals held a 14-13 halftime lead, which they made 17-13 early in the third period with a 22-yard field goal by Neil O'Donoghue.

Then, on St. Louis' next possession, Lomax caught Dallas in a maximum blitz and threw to Green deep. He broke a tackle by Victor Scott and completed the 70-yard play.

Green caught his 45-yarder with 1:39 left in the third quarter, two plays after Tony Dorsett lost a fumble for the Cowboys' third turnover.

St. Louis also scored on its first possession, on a 20-yard throw from Lomax to tight end Doug Marsh, and got a three-yard run for a touchdown in the second quarter by Stump Mitchell. That score was set up by a 44-yard reception by Green, who had eight for 189 yards.