The substitute’s deflected strike cancelled out Youssef El Arabi’s opener in the Europa League last 16 tie in Athens.
Ruben Semedo’s first-half red card in the virtually empty Georgios Karaiskakis Stadium had given Wolves early encouragement but the game will only be memorable for the circumstances it was played in.
Nuno Espirito Santo’s side return from Greece with a positive result in exceptionally trying circumstances, although there is no guarantee next Thursday’s second leg will go ahead.
With a backdrop of a deadly global pandemic, boss Nuno again criticised the decision to play pre-match, calling it absurd.
Wolves had lobbied UEFA to postpone the game – an appeal which was rejected – after Olympiacos owner Evangelos Marinakis announced he had tested positive for coronavirus on Tuesday.
None of the Olympiacos squad contracted the virus after tests earlier in the week but Wolves were baffled at being forced to take what they thought was an unnecessary risk.
Roma’s trip to Sevilla and Inter Milan’s game with Getafe were already off but Wolves made the trip to Athens reluctantly.
The game was already being played behind closed doors because of the Covid-19 outbreak although around 40 vocal guests of the hosts made themselves heard.
There was little early action for the few in the stadium aside from Mathieu Valbuena’s early free-kick flying straight at Rui Patricio.
The game was played at pre-season pace – Wolves looking like they wanted to be anywhere in the world but Athens – yet they were given a boost after 28 minutes when Olympiacos were reduced to 10 men.
The visitors broke quickly and, as Diogo Jota darted towards the box, he was taken out by Semedo.
The defender was immediately dismissed by referee Clement Turpin and Ruben Neves’ subsequent free-kick deflected over.
The dismissal failed to lift Wolves, though, and they struggled to find any intensity in front of the empty seats.
Adama Traore dragged wide just before the break but Wolves fell behind nine minutes into the second half.
Valbuena cut inside to find space and play in Guilherme, whose first touch was exquisite.
The midfielder left Conor Coady standing and then crossed for El Arabi – who scored to knock Arsenal out in the last round – to tap in from six yards.
The striker has now scored in four of his last five appearances for Olympiacos in the Champions League and Europa League.
Wolves responded and Jose Sa saved smartly from Raul Jimenez after he was slipped in by Neto before Neves curled wide from distance.
Nuno’s side had rarely looked a threat before then but they grabbed a fortunate leveller after 67 minutes.
Joao Moutinho touched on a free-kick and Neto’s 25-yard low drive flicked off Andreas Bouchalakis to wrong-foot Sa and earn Wolves a crucial away goal.
It was something the visitors were happy to settle for after all the confusion.