Diego Simeone singled out Atletico Madrid defender Reinildo as the guilty party for allowing Manchester United to equalise late on in the first-leg of their Champions League contest.
The two side's met for the first time since 1991 at the Wanda Metropolitano for a round of 16 contest that has left it all to play for when they reconvene at Old Trafford next month.
The hosts took the lead after Joao Felix scored a delightful header that cannoned off the upright before beating the rooted David de Gea.
Though the game was hardly littered with chances, it felt like Atletico were rarely troubled by the visitors who spent from the from the seventh minute onwards chasing a goal.
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United eventually got one with 10 minutes to spare after Bruno Fernandes found enough space to play in the onrushing Anthony Elanga.
The Swedish teenager made no mistake and calmly slotted his finish beyond Jan Oblak who himself was guilty of some questionable positioning.
Simeone was furious with the way his side had surrendered their lead and targeted Reinildo's part to play in what was a collective lapse in concentration from his defence.
Asked by Marca to analyse the goal his team conceded, Simeone said: "Good play when the ball came out, Bruno makes a pass change and enables the run for a quick transition and they took advantage of the only mismatch we had.
"Reinildo could have solved it better, but we knew that in some transition it could happen."
Fernandes' through ball saw Reinildo desperately try and intercept it via a slide tackle but the former Lille main failed to reach the ball subsequently allowing Elanga a clean run on goal.
Despite the late blow, Simeone has insisted the game is very much still alive as a contest ahead of the second-leg in Manchester.
"Almost everything we did in the game was very good, it would seem that they have the advantage for drawing but nothing changes," he added.
Simeone was clearly seething come the full-time whistle, as he immediately walked straight down the tunnel instead of shaking hands with his counterpart Ralf Rangnick.
The Argentine did not appear to have any kind of fall-out with the United interim boss during the game so is likely to have just wanted to get in the dressing room as quickly as he could.
Atletico's boss does have previous with this kind of behaviour and sparked controversy earlier this season when he opted against shaking the hand of Liverpool manager Jurgen Klopp.
As a result, Simeone explained why he doesn't shake the hand of his opposition.
"I don’t like to shake hands after the game; the emotions are different from the coaches," he revealed.
“I understand that in England, it is used as a gentlemanly way, but I don’t share it because I don’t like falsehoods.
