The Minnesota Vikings sprang the first upset of the 1977 pro football playoffs today when they squelched the Los Angeles Rams, 14-7, in a driving ran, behind reserve quarterback Bob Lee.

The Vikings appeared to have the game put away without an argument, 14-0, until Pat Haden directed a Los Angeles drive that resulted in a touchdown with a little more than a minute to play, scoring on a one-yard lob to Harold Jackson in the end zone.

The Rams then recovered an onside kick and moved to first down on the Minnesota 30 with seven seconds left. Jeff Wright intercepted Haden's desperation pass inside the five-yard line to lock up the decision.

Once more coach Chuck knox suffered a misfortune on a fourth-down call in a big game when the Rams tried for two yards and Lawrence McCutcheon was stopped for no gain in the first quarter.

The Vikings began earning their trip to Dallas on Sunday for the NFC championship game on their first possession, going 69 yards to socre on Chuck Foreman's five-yard run. Lee connected on five straight passes on the drive.

The Vikings scored the insurance touchdown, on a one-yard plunge by Sammy Johnson in the fourth period after workhorse Chuck Foreman's runs set it up.

Haden thrice was intercepted, once in the Minnesota end zone and twice just outside it.

The loss was certain to renew speculation that Knox may be leaving the Rams.

Fran Tarkenton, recovering from a broken leg, did not even make the trip and Bob Lee started at quarterback for the Vikings.

Early on the Rams came up to one of those fourth-and-short challenges that have resulted in so much second-guessing of coach Chuck Knox. This one failed when Lawrence McCutcheon was stopped a yard shy at the Minnesota 31-yard line, where the Vikings took possession.

They were put back to their 22 on a holding penalty against tackle Ron Yary, but Lee took them 78 yards to score.

He hit all five of his passes in the thrust and Chuck Foreman ran five yards for the touchdown. Fred Cox converted.

It was obvious the Vikings wanted to score in a hurry, before the rain-soaked field became unplayable, and then count on their defense to hold the Rams in the slow going.

The Rams tried to move the ball mostly on the ground, which was not productive at first.

In the second quarter, Pat Haden went to the air after defensive tackle Alan Page of the Vikings was offside on a punt by the Rams. That gave Los Angeles a first down at the Minnesota 41.

Haden dared a pass on third and two and connected with tight end Terry Nelson. Then, after the Rams were set back by a holding call against center Rich Saul, Haden passed to Nelson, who broke for 19 yards to the Minnesota nine.

John Cappelletti ran four yards for a first down on the five, but when Haden threw on first down, intended for reserve tight end Charles young, Nate Allen intercepted in the end zone for the Vikings.

Haden later took the Rams to the Viking 31, mostly on a 17-yard run by McCutcheon, but an end-around by Nelson in the mud failed and on third and 10 defensive back Allen held Nelson to a six-yard gain on a pass. Rafael Septien was wide on a 23-yard field-goal attempt.

There was no scoring in the third quarter, but the Vikings got field position that resulted in a one-yard touchdown plunge by running back Sammy Johnson in the fourth period. The conversion by Cox put the Vikings out to 14-0.

That came after Haden was sacked on third and eight at the Los Angeles 22 for a 12-yard loss. Glen Walker punted 51 yards, but Manfred Moore of the Vikings returned 21 yards to the Los Angeles 41.

Foreman ran 10 yards, then 11 to the Los Angeles one and was shaken up on the play. Johnson replaced him and scored on his second try.

The Vikings controlled the ball for 12 minutes 10 seconds in the third quarter; the Rams for 2:50.

The Rams went 60 yards to the Minnesota 20 in the fourth quarter, but a first-down pass to wide receiver Bill Waddy was intercepted by safety Paul Krause at the Minnesota four. He returned it 14 yards to the Viking 18, and only five minutes remained.

The temperature was in the 50s and there was a driving rain that created puddles even though the tarpaulin was not removed until an hour before kick-off.

The Rams were favored by nine points in their third game this year against the Vikings. The Rams won a regular-season game, 35-3. The Vikings won an exhibition, 22-17.