Ukraine came into the match having kept clean sheets in all three of their previous encounters, but faced a side intent on tarnishing that unblemished record. Senegal's unpredictability and willingness to improvise provided a risk in itself, as shown when Sarr flicked the ball up with his heel to set up a volleyed chance in just five minutes. The resultant shot may have been pulled disappointingly wide, but it hinted at the Africans' approach.
Both keepers were required to be at their best, and at the other end Bohdan Sarnavskyi - one of the best on show at this tournament - produced a wonderful save to keep the scoreline blank. Roger Gomis had done everything right, twisting into space at the edge of the box and hammering the ball towards goal. But with the Senegal captain's shot heading for the roof of the net, Sarnavskyi somehow stuck out a hand to tip it over.
That was with 68 minutes played and it became all the more significant within 120 seconds when Ukraine took the lead. The lively Biesiedin was the scorer, making an overlapping run to collect Yevenii Nemtinov's clever reverse pass before opening his body to send a precise right-foot shot into the far corner of the net.
Senegal, though, weren't finished yet and persistence finally paid off for Sarr with seven minutes remaining. Ukraine's perfect defensive record came crashing down in spectacular style as the Young Lions of Teranga star robbed Taras Kacharaba on the edge of the box and gave Sarnavskyi no chance with an unstoppable shot high into the net.
With no further goals in normal or extra time, that left penalties to settle the outcome - and Sy to steal the spotlight. The Senegal keeper whipped up the crowd on his way to take up his position and rose to the occasion, saving from Yevhen Chumak, Yevhenii Nemtinov and Valerii Luchevych as each of Senegal's takers dispatched their kicks with aplomb.