Ron Guidry pitched his sixth career two-hitter and Jerry Mumphrey tripled in two runs in New York last night to help the Yankees to a 3-0 victory over the Toronto Blue Jays on the 60th anniversary of the opening of Yankee Stadium.

"I challenged them. I tried to go right after them. That's the way I used to pitch," said Guidry (1-1), who pitched his first complete game in three starts this season and his first two-hitter since June 1, 1979, when he shut out the Chicago White Sox.

Guidry allowed a leadoff single to Dave Collins in the first inning and then retired 15 batters before Buck Martinez opened the sixth with an infield single.

Collins and Martinez were the only Blue Jays to reach base, Guidry retiring the last 12 hitters after the single by Martinez. He struck out four.

All three New York runs came in the second inning and were unearned as a result of an error by second baseman Damaso Garcia on Roy Smalley's grounder. Graig Nettles walked after Smalley stole second with two out. Mumphrey then tripled, scoring two runs, and Butch Wynegar hit an RBI single.

In off-the-field action, Yankees principal owner George Steinbrenner was fined a reported $50,000 by Commissioner Bowie Kuhn for remarks made in spring training about National League umpires.

"The commissioner has given me his decision," Steinbrenner said in a prepared statement. "I will abide by its terms. I personally regret if in the reporting of the story, the impression was given that I was questioning the integrity of National League President Chub Feeney or the umpires as a group."

On March 25 in Fort Lauderdale, Fla., Steinbrenner was reported by several writers to have said: "The umpires always favor the National League on the close ones. Feeney tells them to."