The Dallas Cowboys were overrun by the Miami Dolphins yesterday, 23-16, for their fourth loss in 10 games.

The Dallas defeat, coupled with the New York Giants' loss to St. Louis, gives the Washington Redskins an added incentive to beat the Colts tonight in Baltimore.

The Redskins (7-2) can expand their NFC East lead to two full games over the Cowboys (6-4) with a victory. The Giants and Philadelphia Eagles, who beat Green Bay yesterday, are both 5-5.

The Cowboys fell behind Miami, 17-0, yesterday but rallied in the fourth quarter. However, a fumble by tight end Billy Joe Dupree stopped one drive and time ran out on Dallas' final surge as Roger Staubach's desperation pass was intercepted on the final play of the game.

The Dolphins ran up a 20-3 lead in the first half.

As in the Cowboy game against the Minnesota Vikings, Dallas fell behind, 14-0, after Miami went 73 yards to score, on a two-yard plunge by Norm Bulaich and on a three-yard scoring plunge by Delvin Williams after Tony Dorsett fumbled and the Dolphins recovered at the Dallas 10.

Garo Yepremian kicked 45- and 23- yard field goals for Miami. Dallas was limited to Rafeal Septien's 30-yard field goal.

Bob Griese came out throwing for Miami and completed nine of 13 passes for 159 yards. Williams caught two passes for 60 yards including a 42-yarder that set up the Dolphins' first touchdown.

Roger Staubach completed seven of 10 passes for 48 yards. He passed 53 yards to wide reciever Tony Hill in the third quarter, but ended up in a second-and-21 situation at the Miami 21-yard line, and Norris Thomas deflected a pass intended for Hill in the end zone.

Septien salvaged three points on a 39-yard field goal to cut Miami's lead to 20-6.

The Cowboys narrowed the Dolphins' advantage to 20-9 on Septien's 24-yard field goal later in the third quarter.

The Cowboys got to the Miami six-yard line on a 19-yard run by Dorset and a 30-yard pass by Staubach to Hill. But on third and five, Coach Tom Landry called for a draw play by Preston Pearson and he was held to a yard gain.