Geoff Zahn pitched a five-hitter and Fred Lynn homered, doubled and singled as the California Angels clinched at least a tie for the American League West championship with a 4-0 victory over the Texas Rangers tonight.

Any combination of California victories and Kansas City losses totaling one will give California's Gene Mauch his first title in 23 years as a major league manager. The Angels are two games ahead of second-place Kansas City heading into the final two games of the regular season. The Royals defeated Oakland, 12-7, to stay mathematically in contention in the division race.

By completing his fourth shutout of the season, Zahn, who had never won more than 14 games in one year, improved to 18-8. Zahn, 35, didn't walk a batter and struck out four.

Zahn allowed only two hits until the Rangers loaded the bases with none out in the ninth on singles by Mike Richardt, Wayne Tolleson and George Wright. He then struck out Billy Sample and Lamar Johnson before retiring Larry Parrish to end the game.

"The ninth wasn't exactly what I had in mind," Zahn said. "But I guess it did provide a bit of drama."

Lynn provided Zahn all the runs he needed with a bases-empty home run in the first inning, his 20th of the season. The two-out homer came off John Butcher (1-5).

"I had a pretty good night, but tomorrow I want to be even better," Lynn said. "We want to get it over with, not drag it out until the last day."

Bob Boone drove in the second California run with a sacrifice fly in the second inning. He scored Doug DeCinces, who led off with a single, went to second when Bobby Grich walked and went to third on Tim Foli's sacrifice bunt. It was Foli's 26th sacrifice of the season.

The Angels extended their lead to 4-0 with two runs in the seventh off Danny Darwin, one scoring on Rod Carew's RBI single and another on a double to left field by Reggie Jackson.