By ANDREW SELIGMAN

CHICAGO – The Cleveland Indians vowed they would be better this season. This was certainly a convincing start.

Grady Sizemore homered off Jose Contreras on the game’s second pitch, and the Indians added four more runs in the first inning on their way to a 12-5 victory over the Chicago White Sox in the season opener Monday.

The 12 runs were the most for the Indians on opening day since 1925, when they scored 21 against St. Louis.

After winning just 78 games last season, Cleveland knocked out Contreras in the second inning and pounded out 13 hits overall.

Sizemore’s homer was the Indians’ first leading off an opener in 19 years. He went 2-for-5 with an RBI and three runs scored.

Trot Nixon had three hits and scored three runs, Travis Hafner had two hits and also scored three times, while Victor Martinez and Jhonny Peralta each had two hits and three RBIs.

That was plenty for C.C. Sabathia (1-0), who pitched well enough after taking a line drive to the left forearm in his final spring start. He allowed three runs and eight hits, struck out two and walked one in six innings.

Darin Erstad hit a two-run homer in the first inning in his White Sox debut. Paul Konerko added a solo shot in the third, but the game was out of reach by then.

A year ago, the White Sox raised the 2005 championship banner before beating Cleveland in the opener. This time, they fell flat.

Contreras (0-1) simply looked more like an old pitcher than his old self. He left with no outs in the second and the White Sox trailing 7-2 after allowing seven hits, walking one and striking out one. After missing the playoffs a year ago, the White Sox are counting on him to perform like the pitcher who started last season 9-0 – not the one who went 4-9 the rest of the way.

Sizemore immediately served notice that Contreras was in for a rough outing, when he drove a 1-0 pitch to the bullpen in right for the eighth leadoff homer of his career. Nixon and Hafner singled to right before Martinez drove in the second run with a single to shallow left. Hafner scored with two outs when Peralta singled on an 0-2 pitch.

Josh Barfield, the next batter, made it 5-0 when he knocked a two-run triple to right-center. The five runs were an Indians record for the first inning on opening day.