The catcher blocked one run in the first inning, slammed a go-ahead home run in the sixth and confidently handled new starter Jose Quintana and three relievers in Chicago's 5-3 victory over the St. Louis Cardinals on Sunday.
"He's hitting fourth, he's catching, he's handling a really good pitching staff, he's throwing people out, he's blocking the ball really well," said Cubs manager Joe Maddon. "And he's hitting homers."
Chicago (51-46) moved into a first-place tie with the Milwaukee Brewers in the National League Central and improved to a season-high five games over .500.
Contreras snapped a tie with a two-run home run, driving in Kris Bryant with his 15th, the top total among NL catchers.
"It feels great (but) it's not about me, it's about the team," Contreras said. "I'm not thinking about first place, I'm thinking about the game that we have tomorrow against the White Sox and keep doing what we've been doing."
The Cubs took two of three in the weekend series and caught Milwaukee (53-48) in the division with their eighth victory in nine games. Chicago has made up a 5 1/2-game deficit on the Brewers since the All-Star break.
The Cardinals (47-51) absorbed their fourth loss in five games and fell 4 1/2 games out in the NL Central.
"We're putting up some good games against some good teams, but something's not letting us finish it one way or the other -- whether it's enough offense or enough pitching and defense," Cardinals manager Mike Matheny said.
"There's enough to be seen that I know the rest of the league knows this team's for real."
Cubs starter Jose Quintana, 2-0 since coming from the Chicago White Sox on July 13 and 6-8 overall, worked six innings for the victory. He allowed three runs on five hits, walked two and struck out seven.
"I was really excited tonight for being the first (game) at Wrigley," Quintana said. "First hitters, I was behind the counts, but I made adjustments."
Cardinals starter Michael Wacha (7-4) pitched six innings in his 100th career start. He allowed five runs on six hits, struck out six and gave up two home runs.
"Curveball was an effective pitch for me tonight, I got some swings and misses, got some big outs for me," Wacha said. "I left a couple cutters -- one cutter over the middle to (Kyle) Schwarber and one to Contreras, both homers."
Cubs closer Wade Davis gave up a leadoff single in the ninth before retiring the next three batters for his 20th save.
Bryant went 2-for-4 to lead the Cubs. Jedd Gyorko, Randal Grichuk and Paul DeJong each had two hits for the Cardinals.
St. Louis was denied in the first as Jason Heyward made a leaping grab at the wall in right for one out, and left fielder Schwarber and Addison Russell collaborated to stop Cardinals leadoff batter Matt Carpenter from reaching home on Gyorko's double with two gone.
Schwarber picked up the ball on a rebound and threw to Russell. The shortstop fired to catcher Contreras, who tagged Carpenter as the pair collided.
Carpenter did not return for the second inning due to right quad tightness. He was replaced by Luke Voit.
St. Louis got on the board in the second with Grichuk's two-run, one-out home run to center in the second. Grichuk, who now has five homers in his past seven games and 12 for the season, drove in Yadier Molina for a 2-0 lead.
The Cubs replied with a pair of third-inning runs as Russell doubled to lead off and came home on Heyward's RBI two-base hit to deep right with two outs. Heyward scored on Bryant's bloop single to right.
DeJong's 12th homer into the left field basket with two outs in the fourth opened a 3-2 St. Louis lead. Schwarber matched it in the bottom of the inning with his one-out blast deep into the right field bleachers for his 15th home run and first since July 14.
NOTES: The Cardinals wound up 4-6 on a road trip that ended Sunday. They open a seven-game home set on Monday as RHP Mike Leake (6-8, 3.39 ERA) goes against Colorado RHP Antonio Senzatela (10-3, 4.67 ERA) in the opener of a three-game series. ... The Cardinals and Cubs meet again in a three-game series in mid-September. ... The crosstown White Sox visit the Cubs for two interleague games on Monday and Tuesday. Cubs RHP Kyle Hendricks (4-3, 4.09 ERA) makes his first start since a seven-week stay on the disabled list after recovering from right hand tendinitis. He goes against White Sox RHP Miguel Gonzalez (4-9, 4.89 ERA). The teams travel to Guaranteed Rate Field for games on Wednesday and Thursday. ... The Cubs did not allow a run in the first inning for the ninth straight game. Until the All-Star break, they had given up 80 runs in the opening inning through 88 games.