McPOWER SURGE

They call Mark McGwire “Big Mac,” but in St. Louis, Cardinal fans are cheering a new member of the “Mac Attack.”

Last week, Keith McDonald, 27, became only the second player in major league history to hit home runs in his first two at-bats, joining Bob Nieman of the St. Louis Browns, who did it on Sept. 14, 1951.

McDonald’s first homer came Tuesday night as a pinch-hitter in the eighth inning, on a 2-2 pitch from Cincinnati’s Andy Larkin.

His second came in his first at-bat as starting catcher on Thursday. He led off the second inning and hit a 1-0 pitch from Osvaldo Fernandez of the Reds into the seats.

“I didn’t even see [the first homer] go out, and I almost tripped on first base,” said McDonald, who played baseball and football at Esperanza High.

After he homered Thursday, the crowd of 43,287 in St. Louis gave him a standing ovation. The fans didn’t stop until teammate Jim Edmonds pushed McDonald back onto the field to acknowledge their cheers.

What did Cardinal Manager Tony La Russa think? “I said, ‘It must be an easy league,’ ” La Russa said. “What a thrill that must be.”

McDonald was called up from triple-A Memphis last Sunday after backup catcher Eli Marrero injured his left thumb attempting to steal second base. McDonald had hit only one home run in 177 at-bats for Memphis this season.

“The fans are probably going to expect it every time,” McDonald told reporters. “But it may be a long time before I hit the next one.”

McDonald, who was drafted in the 24th round by St. Louis in 1994 after playing at Cypress College and Pepperdine, joined Wally Moon (1954) and Eddie Morgan (1936) as the only Cardinals to homer in their first at-bats.