"It's about time," said Mauer after hitting the game-tying solo homer in the seventh inning off Andy Pettitte.
But he just as easily could have been talking about Young's outburst, which came after a rough first two months in Minnesota. He entered the game hitting .264 with no homers and just 15 RBIs after coming over in a trade from Tampa Bay.
"It's not been perfect up to this point but there's a lot of talent there and a lot of ability there," Twins manager Ron Gardenhire said. "We just have to keep pushing along and open up different avenues and different ways to get to him. He's fun to watch."
Young had RBI doubles in the second and sixth innings before giving the Twins the lead for good with another two-bagger off Kyle Farnsworth (0-2) that scored Michael Cuddyer in the eighth.
Young has maintained all season long that he's a slow starter.
"My confidence is always through the roof," Young said. "I don't think it can go any higher."
Mauer hit a solo homer to tie the game, 5-5, and ruin Pettitte's bid for his 170th victory as a Yankee, which would have tied him with Ron Guidry for fourth on the franchise career list.
Pettitte called his decision to throw a four-seam fastball to Mauer on a 1-1 count "just as ignorant a pitch as I could throw."
Mauer's first home run since Sept. 29 slammed off the facing of the upper deck in right field and helped the Twins earn a four-game split.
"It's been a long time coming," Mauer said. "You get that first one, hopefully more will come."
Joe Nathan picked up his 15th save in 16 chances and Matt Guerrier (3-1) pitched 1 2/3 innings of scoreless relief for the win.
Alex Rodriguez had three hits, including a homer, and singled off Nathan in the ninth, but Hideki Matsui grounded into a double play and Jason Giambi lined out to center field as the Yankees ended their road trip at 3-4.
"I'm not happy with it," manager Joe Girardi said outside the Yankees clubhouse. "We should've had a much better record on this road trip. We have to start playing better, and that's the bottom line."
Phillies 5, Reds 4 - Ken Griffey Jr. remained one shy of 600 home runs after getting the night off, but Philadelphia's Chase Utley hit his major league-leading 21st homer to help beat visiting Cincinnati.