Milan woes continue in loss to Malaga
Joaquin curled a penalty off the crossbar in the 45th minute but made no mistake in the 64th when volleying Manuel Iturra's lob pass off the bounce and past goalkeeper Marco Amelia from a tight angle.
Malaga's third straight victory in Group C lifted it to nine points and further compounded Milan's miserable season and called into question coach Massimiliano Allegri's future following a third straight loss. The Italian club has just four points and is 15th in Serie A - 15 points behind champion and leader Juventus.
Milan was at least helped by Zenit St. Petersburg's 1-0 win over Anderlecht. The Russian club has three points, while Anderlecht has one point.
Joaquin didn't let his first-half miss get him down as he dished to Iturra and kept up his run as the Chilean lobbed a return pass to him inside the area to strike the half-volley winner on the run.
The former Spain winger even lifted his arm in celebration before the ball came off the near post and over the line.
''I just kept believing,'' Joaquin said. ''We did this with our philosophy of play. We should celebrate this.''
Milan had started well enough at La Rosaleda Stadium with Giampaolo Pazzini shaving the crossbar with a curling free kick in the ninth minute.
Despite a number of prodding shots from long range, Milan couldn't string much together inside its opponent's area as Malaga slowly took command of the game through Francisco ''Isco'' Alarcon.
Isco had a pair of efforts come close before Kevin Constant was booked for taking Jesus Gamez down inside the area as they chased a ball in the 43rd.
But Joaquin couldn't take advantage with his spot kick, although the hosts came out of the break just as determined and their intensive play paid off with Qatari owner Sheikh Abdullah Bin Nasser Al-Thani watching from the stands for the first time since May.
Malaga's Champions League expectations were modest after star players like Santi Cazorla were sold in the offseason.
''Nobody imagined this. We didn't know what would happen each morning and look at what's happening now,'' Joaquin said. ''I think all of Malaga made history today. Milan's not in its best moment but it's still a top club.''
Milan `keeper Marco Amelia tipped Eliseu's dangerous shot wide in the 66th, and it would be nearly 20 minutes before the Rossoneri tested Willy Caballero again. The Argentine goalkeeper saved from Stephan El Shaarawy in the 85th from close range as Malaga has yet to concede a goal.