Anderlecht's hopes of progressing against Zenit St Petersburg appeared over after the Russians overturned a 2-0 first leg deficit.
Anderlecht's hopes of progressing against Zenit St Petersburg appeared over after the Russians overturned a 2-0 first leg deficit to lead 3-2 with seconds remaining.
But Kiese Thelin's decisive intervention earned Anderlecht an unlikely ticket to the last 16 to keep alive their dream of a first continental honour since their 1983 UEFA Cup triumph.
It was the 24-year-old Swedish international's first goal for the club he joined last month on loan from French Ligue 1 outfit Bordeaux.
Ajax had lifted the UEFA Cup the season before Anderlecht and the Dutch giants made it into the next round courtesy of defender Nick Viergever's close-range finish in the 49th minute against Legia Warsaw.
The only goal over the two legs put Ajax through by the slimmest of margins.
Also progressing were Roma, 4-1 on aggregate despite Villarreal taking the second leg 1-0, Besiktas, APOEL and Olympiakos.
On Wednesday Manchester United cruised into the last 16 with a 1-0 win at Saint Etienne for a 4-0 aggregate success.
Also surviving to live another day in Europe's second tier competition on Wednesday were Schalke and Russian outfit Krasnodar, who saw off Fenerbahce.