Oscar Tabarez's side slumped to an embarrassing defeat, losing their first game ever in their Olympic history in the process, bringing an end to an 88-year unbeaten run
Senegal continued their good form in their maiden Olympic Games tournament with a surprise 2-0 victory over an out-of-sorts Uruguay side, despite going down to ten men in the first half.
Both sides went into the game off the back of decent results in the opening group games, but it was the African side which took the initiative in the ninth minute, with Moussa Konate tapping home a rebound from a corner.
They had a man sent off just after the half-hour mark, though, when Abdoulaye Ba barged over Luis Suarez and deemed to have prevented a clear goalscoring opportunity. Nevertheless, Konate struck again in the 37th minute, nodding home unmarked to expose this Uruguay defence's vulnerability from set-pieces.
Senegal made two changes to the side that managed to snatch a late draw against Great Britain in their group opener, with Stephane Badji and Cheikhou Kouyate coming in for Ibrahima Balde and Idrissa Gueye.
Uruguay coach Oscar Tabarez, made just the one change to his starting eleven, bringing in Nicolas Lodeiro, who struck the match-winner in their 2-1 victory over the United Arab Emirates, in place of Matias Aguirregaray.
The South Americans began the brighter of the two sides, with Gaston Ramirez striking a free kick from distance narrowly over in the second minute, but Senegal responded well with a decent spell of possession, gradually pushing their way up the pitch.
And they went on to take the lead in the ninth minute through Konate, after he poked home from barely a yard out after Uruguay goalkeeper Martin Campana could only parry Kouyate's diving header at the back post.
With Uruguay struggling to retain possession and create anything further forward, their best chance of the half came in the 27th minute when Ramirez struck another superb free kick from 30 yards out which came off the inside of the post before being hacked clear, with Mane rooted to the spot.
The game was turned on its head moments later, when the already booked Ba was given a straight red card for cynically barging over Suarez.
This brought the game to life, with Saliou Ciss clearing a toe-poked Arias effort at the back post off the line with the increasingly erratic Mane nowhere to be seen yet again.
Despite only having ten men, though, Senegal extended their lead in the 37th minute with Konate nodding in his second of the match and third of the tournament with the Uruguay defence static, with Souare again credited with the assist, picking out the only green shirt in the entire six-yard box.
La Celeste started the brighter of the two again in the second half, with Ramirez again threatening from range with a free kick shortly after the restart. The Bologna man then set up an excellent chance for substitute Abel Hernandez, dinking a delightful ball over the back four, before the youngster saw his effort well blocked.
With Senegal struggling to get out of their half, Uruguay broke at pace, with Hernandez playing in Cavani, but the Napoli forward's poor form throughout the tournament continued as he pulled his effort miles wide, with Suarez well placed further inside and begging for the ball to be played in to him.
On the hour mark, Liverpool striker Suarez, who was enduring a bad afternoon at the office, nodded narrowly wide with the goal gaping after peeling off his marker at the back post.
With chances few and far between after that, though, the game petered out into a scrappy affair, with both sides seemingly incapable of stringing more than two passes together, with only a lacklustre Suarez going close in the final stages after latching onto a Coates flick-on.