Tony Clark hit a three-run homer as Detroit ended a four-game losing streak and salvaged one victory in a five-game homestand. Brian Hunter and Damion Easley hit solo home runs for the Tigers.
McGwire became only the fourth player to clear the left-field roof with a blast that took one hop near a light tower and bounced over.
Even Moehler, who also gave up a solo home run to Dave Magadan in the second inning, was excited about giving up McGwire's blast.
"I don't usually watch my home runs, but I had to watch that one," Moehler said. "It's sort of an honor."
The only other players to clear the left-field roof were Harmon Killebrew in 1962, Frank Howard in 1968 and Cecil Fielder in 1990.
Moehler (1-1) gave up two runs on eight hits in seven-plus innings.
Baltimore 11, Boston 1--Jerome Walton went three for three, extending his hit streak to seven consecutive at-bats, as Jimmy Key and the Orioles defeated the Red Sox at Boston.
It was 8-0 before Shane Mack's run-scoring single with two outs in the sixth chased Key (3-0) and ended his shutout string at 14 innings.
In a start originally scheduled for Friday before two consecutive rainouts, Key gave up five hits and overcame a career-high six walks.
Walton scored two runs and drove in one. He also walked and has reached base in eight consecutive plate appearances.
Cleveland 6, Milwaukee 4--Chad Curtis led off the sixth inning with a tiebreaking home run, helping Orel Hershiser and the Indians beat the Brewers at Cleveland.
Hershiser (1-0) bounced back from a third inning in which he made a throwing error and hit two batters.
Starting for the fourth time this season, Hershiser earned his first victory since Sept. 21. He hit a career-high three batters in 6 1/3 innings.
Curtis homered off Bob Wickman (2-1) for a 5-4 lead.
Griffey tied Colorado's Larry Walker for the major league lead in homers with a two-run shot in the fifth.
Russ Davis had three hits, including two doubles, for Seattle. Ron Coomer and Todd Walker homered for the Twins.
Todd Ritchie (2-2) relieved to start the sixth with the Twins ahead, 5-4. But he retired only one batter while giving up three runs on three hits and a walk.
Chicago 8, New York 7--Tony Phillips drew a bases-loaded walk from Yankee reliever Brian Boehringer with two outs in the bottom of the 11th inning after a bizarre argument, and the White Sox won at Chicago.
The Yankees lost for the second time in four days on a bases-loaded walk. Thursday, David Weathers walked Milwaukee's John Jaha with one out in the ninth, forcing home the winning run.
Ron Karkovice doubled with two outs in the 11th off Boehringer (0-1). Ozzie Guillen was intentionally walked and Ray Durham followed with a walk to load the bases.
Phillips, known for his ability to draw walks, got ahead, 3-1, in the count. He then began arguing with first base umpire John Shulock, who told Phillips to get back into the batter's box. When he returned to the plate, he took ball four. Boehringer had words with Shulock on his way to the dugout.
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BESTS OF THE DAY
Player Team Performance Team's Result Jerome Walton Baltimore 3 for 3, seven consecutive hits Win Dean Palmer Texas 2 for 4, 2 HR including Win grand slam, 5 RBI Dan Wilson Seattle 2 for 2, double, triple, 2 RBI Win
Player Team Performance Jimmy Key Baltimore 5 2/3 innings, 5 hits, 1 run, 6 strikeouts Orel Hershiser Cleveland 6 1/3 innings, 6 hits, 1 earned run, 7 strikeouts Brian Mohler Detroit 7 innings, 2 runs in first major league victory
Player Team's Result Jimmy Key Win Orel Hershiser Win Brian Mohler Win