DETROIT ? Dee Brown has no idea why he’s been so successful against the Detroit Tigers throughout his career. Whatever the reason, he’s sure to be in the starting lineup whenever the Kansas City Royals play them.

Brown had his first career two-homer game and drove in four runs, leading the Royals to a 6-2 victory Tuesday night.

Brown has six career homers against Detroit and just eight against the rest of the majors. He has homered twice against the Twins and once each against six teams.

“I don’t know if I just see the ball well here or what — it’s a really big ballpark,” Brown said. “It’s better this year, but their pitching hasn’t been very good in the past.”

Royals manager Tony Pena doesn’t have an explanation either, but plans to ride the hot hand.

“I guess I better keep playing him against the Tigers,” he said.

Jimmy Serrano (1-1) picked up his first major-league victory with three scoreless innings of relief, helping the Royals win for just the fifth time in 16 games.

“That was exciting,” he said. “I’ve got the ball and the scorecard.”

Serrano, who hadn’t pitched since Aug. 28, walked the first two batters he faced, but only allowed one more base-runner.

“I just wanted to go out there and throw strikes,” he said. “And after the first two batters, I still wanted to do that. I was a little rusty, but I was able to settle down and get in a groove.”

Carlos Pena and Craig Monroe homered for the Tigers, who had their two-game winning streak end.

“That’s baseball,” Monroe said. “It’s tough to lose, but a lot is going to happen in a nine-inning game, and tonight, all the good things happened for them.”

Nate Robertson (12-8) allowed five runs and nine hits in six-plus innings, losing for the first time in four starts.

“I thought I was controlling the game pretty well early on,” Robertson said. “But I started missing some pitches and they made me pay for it.”

Pena’s career-high 20th homer in the second and Monroe’s 14th homer in the fourth — both off Brian Anderson — gave the Tigers an early 2-0 lead.

Joe Randa, who went 3-for-4, led off the fifth with a double and took third on Calvin Pickering’s infield single. Brown made it 2-1 by grounding into a force at second, then moved to third on John Buck’s double to left.

Ruben Gotay tied it with a single, but Buck slipped rounding third and was thrown out trying to get back to the base. Robertson then retired David DeJesus to get out of the inning.

Kansas City went ahead in the seventh when Randa led off with another double and scored on Pickering’s single to center. Brown then made it 5-2 lining a 3-1 pitch from Robertson just inside the right-field foul pole.

Kansas City had runners on second and third with no outs later in the inning, but reliever Al Levine got out of the jam.