A 90th-minute goal from Roberto Ovelar has seen Juan Aurich stun Universitario 1-0 in Peru's Primera Division.
Both second phase group leaders in the Primera Division dropped points as Group A's top team Real Garcilaso were held to a 1-1 draw away to Union Comercio and Group B's Universitario suffered their first defeat in nine games.
But Universitario's loss did not hurt the capital club too much as the next four clubs in Group B all failed to win.
Universitario had to play about an hour with 10 players after Nestor Duarte was shown a red card in the 32nd minute for a raised arm to Ovelar's face.
Despite having one more player for most of the match, Juan Aurich rode their luck at times on Thursday with Universitario wasting a number of counter-attack opportunities after half-time.
But in the final minute of regular time, Juan Aurich finally made their extra man count when Ovelar did well to control Jeikson Reyes' cross from the left wing on his chest and then side-footed the ball into the net.
The loss left Universitario on 57 points but with second-placed Inti Gas also losing 3-1 away to Universidad San Martin, the Group B leaders remain eight points clear at the top of the table.
UTC Cajamarca, Leon de Huanuco and Cienciano also failed to make significant inroads into Universitario's leading margin.
Cajamarca and Cienciano drew 2-2, while Leon lost 1-0 to Jose Galvez.
In Group A, bottom-placed club Union Comercio shared the points with Real Garcilaso.
Roberto Jimenez produced a smart finish to give Union Comercio the lead in the 13th minute and although Mauricio Montes equalised for the visitors six minutes before half-time, the home side held on for a draw.
Second-placed Sporting Cristal, who have a game in hand on Real Garcilaso, could move within a point of the Group A-leaders if they knock them off on Sunday.
In the other midweek game, Sport Huancayo defeated Pacifico 2-1.