Steve McClaren's FC Twente were knocked out by an own goal in the dying moments of their Champions League third qualifying round match with Sporting Lisbon, having led since the second minute.
A 1-1 draw in Enschede sent the Portuguese side through on away goals but for the majority of the match it seemed Brazilian defender Douglas' early strike would be enough.
The Dutch side were seconds away from reaching the play-offs when Sporting goalkeeper Rui Patricio, up for a last-gasp corner, helped bundle the ball into the six-yard box where home defender Peter Wisgerhof steered over his own line.
Dimitris Salpingidis scored with a minute to go to seal Panathinaikos' place in the play-off round of the Champions League and edge out Sparta Prague.
Having lost the third qualifying round first leg 2-0, the Greek side had plenty to do in the return match.
Jose Sarriegi put them one up before Kostas Katsouranis levelled the aggregate scores, paving the way for Salpingidis to settle the tie 3-0 in dramatic fashion.
Elsewhere, Israel's Maccabi Haifa completed a remarkable comeback against Kazakhstan's FC Aktobe to progress with a 4-3 win.
Having drawn 0-0 first time around, Haifa slumped to 3-0 behind in the first 15 minutes before goals from Yaniv Katan, Eyal Golsa and two from Vladimir Dvalishvili saw them to victory.
Belgian side Anderlecht lost 3-1 to Turkey's Sivasspor on the night but relied on a comfortable first-leg cushion to take a 6-3 aggregate win.
Jelle Van Damme scored the consolation, with Ersen Martin, Yannick Kamanan and Aydin Musa on target for Sivasspor.
Salzburg emerged victorious from their encounter with Dinamo Zagreb thanks to Robin Nelisse's 83rd-minute decider.
The Austrians won the tie 3-2 - 2-1 on the night - as goals from Dusan Svento and Dimitrios Papadopoulos cancelled each other out before Nelisse struck.