The Twins will be up against a left-handed starter for the second time this season Tuesday night when they face Jason Vargas, who has fared poorly at Target Field.
Minnesota (5-7) ended a five-game slide with Monday's 8-2 rout in the opener of this three-game set. Mauer went 4 for 5 with a homer and is now hitting .412 over an eight-game hitting streak.
His homer was his second in his last 36 home games and sixth overall at Target Field.
"The ball was carrying better today,'' Mauer said. "I've been disappointed in previous seasons, but tonight it was just flying a little bit better."
One of Mauer's hits was an RBI single in the sixth inning off Angels left-handed reliever Michael Roth for a 5-2 lead. The star catcher entered 2 for 9 against left-handers.
That's still better than Morneau, who grounded out against Roth to drop to 2 for 12 against left-handers.
Minnesota went 22-29 against left-handers a season ago for the AL's second-worst mark. Mauer hit .287 against lefties in 2012 (compared to .336 against right-handers) and Morneau was at .232.
Vargas (0-1, 4.76 ERA) has limited Mauer to four hits in 15 at-bats and Morneau to three in 12.
The Angels starter, however, is 1-1 with an 8.22 ERA in three starts at Target Field.
Los Angeles (4-9) has dropped both of Vargas' starts this year. He has lasted 5 2-3 innings both times, allowing five runs in Thursday's 8-1 defeat to Oakland.
Vargas won't see left-handed hitting Oswaldo Arcia, who went 1 for 3 and dropped a routine pop fly for an error in his big league debut Monday. Arcia joined the team from Triple-A Rochester and started in place of Josh Willingham, who was sick.
The highly regarded prospect was sent back to the minors after the game. Outfielder Wilkin Ramirez has been reinstated from paternity leave.
This series pits clubs with two of the worst starters' ERAs in the majors, with Los Angeles at 5.72 and Minnesota at 5.88. No Angels starter has lasted seven innings.
"I don't know if you can put it all on the starting pitching, but you talk about it being the heartbeat of the club. It's where everything starts,'' Angels manager Mike Scioscia said.
Mike Pelfrey (1-1, 7.36) will start Tuesday as he looks to recover from last week's rough outing in which he yielded six runs over two innings in a 7-4 loss at Kansas City.
The right-hander is 2-0 with a 4.20 ERA in two career starts against the Angels. He's never faced Mike Trout, who has three straight multihit efforts for Los Angeles.
Albert Pujols, meanwhile, is a career .194 hitter with no homers at Target Field.