Ajax booked their place in the last 32 of the Europa League courtesy of a come-from-behind 2-1 victory at nine-man FC Timisoara - despite missing two second-half penalties.
Dorin Goga stunned the visitors with the game's first goal inside two minutes but Luis Suarez equalised six minutes later and Marko Pantelic put the Amsterdam giants ahead soon after the restart.
Defender Eder Bonfim and goalkeeper Costel Pantilimon were both given their marching orders in the second half. Suarez saw both the resulting penalties saved but Timisoara could not capitalise.
The outcome left Martin Jol's side three points clear of second-placed Anderlecht, whose qualification for the knockout phase is by no means assured following their 1-0 defeat at home to Dinamo Zagreb.
Ajax headed to Romania knowing they needed only a draw to ensure their progress but were caught napping in the second minute as Timisoara opened the scoring with the first attack of the game.
Goga latched onto Gheorghe Bucur's pass and slotted his shot into the bottom-left corner of Maarten Stekelenburg's net.
Suarez looked to respond immediately with a close-range effort that flew just wide of the Timisoara goal but the Uruguay forward did find the target in the eighth minute - his neat shot into the bottom-right corner getting Ajax back on level terms.
Stekelenburg had to be on his toes to prevent the Romanian outfit regaining their lead, catching another blast from Goga and then parrying an effort from Ioan Mera.
Pantilimon at the other end was also kept busy, diverting a long-range Suarez attempt to safety before watching Jan Vertonghen's header from Urby Emanuelson's free-kick drift just wide.
The 8,085 crowd did not have long to wait for the third goal after the break, Pantelic latching onto Demy De Zeeuw's pass and slotting into the bottom-right corner from 12 yards within a minute of the restart.
It all looked to be falling apart for Timisoara four minutes later when Bonfim was dismissed for a professional foul on Mitchell Donald inside the area but Suarez's spot-kick was well saved by Pantilimon low to his right.
Suarez had the chance to make amends just after the hour when he was brought down by Pantilimon, earning the Timisoara stopper a red card, but the Ajax frontman was again foiled from 12 yards - this time by replacement goalkeeper Pedro Taborda.
The visitors continued to push for a third goal to give themselves some breathing space and twice came within a whisker when first substitute Miralem Sulejmani and then Pantelic both struck the bar, but they had already done enough.