Mike Aviles hit a grand slam in the third inning and drove in five runs and the Kansas City Royals defeated the Oakland Athletics, 8-3, on Tuesday night.

Royals right-hander Zack Greinke, who had given up 11 runs in eight innings in his previous two starts, struck out eight in five innings and allowed three runs, two earned, on four hits and two walks.

Oakland’s runs came off Greinke in the third. Nomar Garciaparra and Bobby Crosby had RBIs, while the other run scored on Alberto Callaspo’s throwing error.

After the game, Kansas City manager Trey Hillman made it official — Gil Meche would start the April 6 opener at Chicago, while Greinke would start the second game.

Aviles, who started last season at Triple-A, was promoted on May 29 last season and became the Kansas City regular shortstop on June 6, hitting .325 with 10 home runs and 51 RBIs in 102 games. He finished tied for fourth in the American League rookie of the year balloting.

“It’s a complete 180, definitely for the better,” Aviles said of the turnaround of his fortunes from the 2008 camp. “I’m not saying it was bad in 2007, but it’s a lot different now. I can’t complain. I worked really, really hard to be where I’m at right now. I’m going to work harder to stay where I’m at and get better. That’s usually my philosophy, just work as hard as I can and leave everything out there.”

Aviles’ grand slam off A’s left-hander Josh Outman came on a change up. Willie Bloomquist and Coco Crisp had singled and Alex Gordon was hit by a pitch to load the bases.