KANSAS CITY (Reuters) - The Cleveland Indians scored four runs in the 10th inning to beat division rivals Kansas City 7-3 on Monday and continue their hot start to the season.

Shelley Duncan delivered a pinch-hit RBI double to break a 3-3 tie in the 10th as the Indians captured their fourth consecutive win and opened up a two-game lead over the Royals in the American League Central.

Kansas City (10-6) and Cleveland have been division bottom dwellers in the last couple seasons, but the Indians (12-4) are now off to their best start since 1999.

Three-times All Star Grady Sizemore showed little signs of rust in his second game back from a knee injury that had sidelined him since last May. Sizemore had an RBI in the 10th and finished with three hits after going 2-for-4 with a home run on Sunday.

"One of the reasons I came here was to enjoy watching this guy from the dugout," Indians manager Manny Acta told reporters of Sizemore. "It's nice to have him back."

Kansas City scored a run in the second and added two more in the sixth to take a 3-2 lead. Billy Butler went 2-for-3 with a run scored for the Royals.

Indians starter Carlos Carrasco pitched 6 1/3 innings of a no-decision. Reliever Joe Smith recorded the win after throwing 1 1/3 scoreless innings before Justin Germano got the final three outs.

"I've been here 2009, 2010 and we haven't been battling for first place," Smith said. "We're off to a hot start, playing the team right behind us in our division. Now's the time to really gain some ground."

Kansas City's Tim Collins took the loss after allowing all four runs in the 10th.

(Reporting by Jahmal Corner in Los Angeles; Editing by Peter Rutherford; to query or comment on this story email sportsfeedback@thomsonreuters.com)