Backed by a pair of homers. Mike Cuellar wins his 10th straight for the first-place O’s, beating Detroit’s Joe Coleman, 3 – 2.

In the opener of a twin bill between Pittsburgh and Chicago, Roberto Clemente hits his 3rd and 4th Wrigley Field round-trippers in two games. The first blast puts Pittsburgh up, 2 – 1, in the 3rd, and the last provides the Pirates’ final two runs in the 10 – 6 win. With Clemente resting in the second game, the Cubs salvage the split, 7 – 2, behind Milt Pappas, with Pittsburgh falling half a game behind division-leading New York.

The Cards send three pinch hitters to the plate in the 8th inning and all three strike out. Steve Renko of the Expos fans 10 in the game, including Jim Beauchamp, Vic Davalillo and Leron Lee in the 8th, to give Montreal an 8 – 0 win.

Brothers Billy and Tony Conigliaro both hit home runs in the Red Sox’s 5-1 victory over the Tribe at Fenway Park. The Boston outfielders become the eighth different set of siblings to have homered in the same game, a feat which has occurred only 13 times in major league history.

The Dodgers take first place in the National League West by sweeping a doubleheader against the Braves in Los Angeles, winning 6 – 7 and 7 – 3.

At Kansas City’s Municipal Stadium, Bob Oliver becomes the first player in Royals history to hit a grand slam. The center fielder’s eighth-inning blast comes off Jim Bouton of the Pilots in an eventual 13-2 KC victory.

In Minnesota, Mudcat Grant stops the Yankees to give the Twins an 8 – 3 victory. Mickey Mantle drives in all three New York runs with two homers.

Philadelphia C Clay Dalrymple collects six walks in a 19-inning doubleheader against the Astros. The Phillies win the first, 9 – 0, and take the nightcap, 4 – 3, in 11 innings.