Andre Onana atoned for an earlier mistake by making two superb late saves to help Ajax edge closer to the Champions League last 16 with a 1-1 draw at Benfica.
A victory would have been enough for the Eredivisie side to guarantee progression from Group E, but Erik ten Hag's men fell behind in the 29th minute when Jonas capitalised on Onana's calamitous error.
But with Jonas spurning a great opportunity to make it two, Benfica were punished midway through the second half when Dusan Tadic forced home from a tight angle.
The hosts rallied, but Onana went from villain to hero when he pulled off a pair of outstanding stoppage-time saves to deny Rafa Silva and Gabriel Pires and secure a point which puts Ajax on the verge of the knockout stages.
Benfica were rewarded for a positive start just before the half-hour mark when Onana, having had to clear his lines following an attempted Cruyff Turn in his own six-yard box, flapped dreadfully at the resulting throw-in, with Jonas on hand to tuck home.
Jonas could have doubled his tally soon after, but he failed to connect properly with Alejandro Grimaldo's free-kick, and that miss almost proved costly on the stroke of half-time.
Lasse Schone's free-kick caused havoc for Odisseas Vlachodimos, but neither Donny van de Beek or Frenkie de Jong could apply the finish from the rebound.
But Ajax had their equaliser just after the hour – Hakim Ziyech playing in Tadic, who managed to squeeze in a finish despite Vlachodimos' best efforts.
However, it was Onana who came to Ajax's rescue late on, first denying Silva before pulling off an equally as impressive stop to keep out Gabriel's effort from the following corner.
What does it mean? Benfica on the brink
With Bayern Munich beating AEK Athens, Benfica would have been out had they lost at Estadio da Luz. And even though Rui Vitoria's side – who face Bayern in their next Champions League outing – may still be in with a chance of progressing, a point against AEK will be enough for Ajax to secure a last-16 berth if Benfica fail to win in Germany.
Jonas returns in style before injury scare
Having missed a large chunk of the campaign with a back injury, Jonas returned to scoring form in the defeat to Moreirense last time out, and marked his first Champions League appearance of the season with a typically composed finish following Onana's howler, only for his European comeback to ultimately be cut short by injury.
Onana spares his own blushes
Ajax had not conceded a goal in any competition since October 2, but Onana's recklessness put them on the back foot. And while the goalkeeper must cut out such rookie mishaps, the Cameroon international certainly did his best to make up for it with those excellent stops in the final minutes.
Tondela are next up for Benfica, while Ajax will look to keep within touching distance of Eredivisie leaders PSV Eindhoven when they face Excelsior on Sunday.