OAKLAND, Calif. — Jon Lester won his Oakland debut while pitching into the seventh inning and Jonny Gomes got two hits during an eight-run burst in his return to the Athletics as they beat the Kansas City Royals 8-3 Saturday.

Two days after being traded from the sagging World Series champion Boston Red Sox, Lester and Gomes teamed up to boost the club with the best record in baseball.

The 6-foot-4 Lester (11-7) instantly became an imposing presence on the mound in the pitcher-friendly Coliseum. Fans in the crowd of 30,097 cheered the lefty as he went through his warmup routine in left field, then Lester tipped his cap to a roaring ovation when he left after 62/3 innings.

Back with the AL West-leading A’s, Gomes delivered in an eight-run fifth inning. He singled and scored off Jason Vargas (8-5), then hit a two-run single off Aaron Crow.

Lester gave up three runs and nine hits, walking one and striking out three.

Pitching on seven days’ rest after being scratched Wednesday ahead of the trade deadline, Lester improved to 8-3 with a 2.20 ERA in 12 career starts against the Royals. He hasn’t lost in nine starts overall since June 7 at Detroit.

The A’s went ahead with their planned promotion, passing out 10,000 Yoenis Cespedes T-shirts reading “La Potencia” – it pays tribute to his power. The two-time Home Run Derby champ was traded to Boston in the big trade.

Vargas came off the disabled list to make his first start since undergoing an appendectomy July 9. After the first 12 A’s batters were retired in order, the next 12 produced eight hits and eight runs.

Oakland lost second baseman Nick Punto when he strained his right hamstring. He rounded third on Jed Lowrie’s RBI single in the fifth, but slid toward the coach’s box and grabbed the back of his leg before hobbling back to the bag.

An inning earlier, the umpires went to replay to determine whether A’s catcher Derek Norris improperly blocked the plate when he tagged a sliding Alex Gordon. The out call was confirmed, with newly acquired center fielder Sam Fuld’s throw resulting in a sensational double play.

NOTES

ROYALS: First baseman Eric Hosmer was put on the 15-day DL with a stress fracture of the third finger on his right hand. He is expected to miss 3 to 6 weeks.

ATHLETICS: Center fielder Coco Crisp missed his sixth straight game with a strained neck. Manager Bob Melvin said the A’s aren’t putting him on the DL because Crisp has shown he can make progress once back doing baseball activities, which could be Sunday.

DODGERS: Lefty Paul Maholm is on the 15-day DL because of a torn right ACL that which will sideline him for the rest of 2014.

BRAVES: Popular former broadcaster Pete Van Wieren died Saturday morning following a long battle with cancer. He was 69.

Known as “The Professor” for his encyclopedic knowledge of the game, Van Wieren spent 33 years broadcasting Braves games on television and radio, and was inducted into the Braves Hall of Fame in 2004.

INDIANS: Jim Thome’s point-the-bat hitting stance, a powerful symbol of the most successful era in team history, is now a permanent fixture at Progressive Field. The Indians honored their career leader in homers by unveiling a statue of Thome – his bat pointed menacingly at the pitcher – to rest in the center field monument area.

DIAMONDBACKS: All-Star first baseman Paul Goldschmidt, who leads the league in doubles and extra-base hits, fractured his left hand in Friday’s loss to Pittsburgh and is headed to the DL.