Pitcher Rick Reuschel singled with two out in the 13th inning and scored on singles by Steve Ontiveros and Dave Rosello today to give the Chicago Cubs a 16-15 victory over the Cincinnati Reds in a game that tied major league records for five home runs in an inning and 11 overall.

Reuschel, coming on in relief in the top of the 13th as the Cubs' seventh pitcher, boosted his record to a major league-leading 15-3 after having blanked Cincinnati Tuesday on five hits. Jack Billingham, 8-8, took the loss.

The Reds took the lead at 15-14 in the 12th on George Mitterwald's second homer of the game and the 11th for both teams. The last time 11 homers were hit in an extra-inning game was Aug. 12, 1966, when Pittsburgh had six and Cincinnati five in 13 innings.

The Reds smashed five home runs three in the first inning - and the Cubs had six - two in the first. The five homers in one inning tied a major league record.

Ken Griffey, Pete Rose, Bench, Mike Lum and Cesar Geronimo homered for the Reds. Bill Buckner and Mitterwald had two each for the Cubs with Bobby Murcer and Jerry Morales hitting one apiece.

The Cubs tied the score at 14 with two out in the ninth when Murcer singled, moved to second on a walk to Morales and scored on Ontiveros' single.

The Reds scored six runs in the first when Rose hit a solo homer, Bench a three-run drive and Lum a two-run homer. But the Cubs replied with four runs when Buckner hit a three-run homer and Murcer a solo shot. Mitterwald homered for the Cubs with none on in the second, when they scored three times to go ahead, 7-6.

The score was tied at 10 when Ken Griffey homered in the sixth and he boosed the Cincinnati margin to 13-10 with a double in the seventh after the bases had been walked full. Cesar Geronimo homered to open the eighth inning.

The Cubs pulled within one run with a three-run eighth when Buckner hit his second homer with a man on, to give him five RBI, and Morales hit a solo drive.