MILAN, Italy -- Who knows exactly what thoughts lurked inside the head of Theo Hernández, just beneath his shocking pink tufts of hair, when he made the most boneheaded of decisions five minutes into the second half of AC Milan's Champions League playoff second-leg clash against Feyenoord?

Games don't often turn on individual players and moments of startlingly bad decisions. This one largely did, and it cost Milan a place in the Champions League round of 16.

A goal down from the first leg, Milan needed to win by two to advance. They got halfway there within 60 seconds of the opening kickoff: a Christian Pulisic cross, a Malick Thiaw nod back across goal and new signing Santi Gimenez on hand to tuck it in.

One-nil up and 89 minutes (plus injury time) at home, in front of their fans, to notch the second. It seemed easy-peasy when you consider their opponents, Feyenoord -- who haven't been good since Arne Slot left for Liverpool nine months ago and whom already fired his successor, Brian Priske -- were missing no fewer than 10 players and were starting three teenagers as a result.

Milan were squarely in control of the first half and missed several chances to double the lead. They started brightly in the second half going close to scoring again ... but then came Theo's lapse.

Rafael Leão fed his full-back on an overlap as Theo sliced into the penalty area, duly ran at defender Givairo Read and ... very obviously tumbled over his leg, with no contact at all. Referee Szymon Marciniak had no choice but to show him the yellow card ... and then a red one too.

Why? Theo had already been cautioned at the end of the first half, a booking as needless as this one. The first was for a pointless foul on Jakub Moder in the center circle, which erupted in a melee that left Theo's adversary on that flank, Anis Hadj Moussa, needing to be physically restrained.

Some might be inclined (in a Machiavellian, Dark Arts sort of way) to justify trying to con the referee to win a penalty, but there's a time and a place for it. This wasn't it. It was classic risk-reward type stuff made worse by the fact that the way Milan were playing at the time, the second goal was bound to come.

After the match, Milan officials went out of their way to avoid scapegoating Theo, but it's not hard to read between the lines.

"The face of Milan's defeat ought to be my face, not Theo's. ... I'm the one responsible," Milan boss Sérgio Conceição said after the game. Club icon (and now senior adviser) Zlatan Ibrahimovic echoed the sentiment: "The referee was tough: in a game like this you usually just give a warning. ... We're not angry at Theo, we're angry at ourselves, we committed suicide out there."

Feyenoord's fans -- cooped up high in the third tier of the San Siro -- celebrated him marching off the pitch as if they had just scored themselves. They understood the situation -- certainly better than Theo.

The tie was 1-1 on aggregate at that point, but Milan couldn't just sit back and play for penalties. They were the home side, they were the pedigreed team, they were the ones lining up with four forwards (from left to right: Leao, João Félix, Gimenez and Pulisic) and they were built to attack. Perhaps they also knew that playing a man down for nearly an entire second half (plus injury time) was going to be a big ask.

Suddenly, the tide was flowing Feyenoord's way: Julián Carranza's header with 17 minutes to go tied the score on the night and put Feyenoord ahead on aggregate.

Milan were never coming back at that point and to make matters worse, frustration began to show. Conceição probably didn't help matters with his changes, though he defended them with his usual posturing at the final whistle: "I'm paid to make decisions: If I don't win, they'll pack my bags for me and send me away."

What did he do? First, he withdrew Pulisic and then Gimenez, leaving Félix and Leão on the pitch. In a situation like this at 10 vs. 11, you would have thought the former duo's work-rate would be more desirable than the flighty skills of the latter pair. And indeed, Leão looked like a boy racer happily speeding into cul-de-sacs, before getting shown a red card of his own in a pointless postmatch melee.

Meanwhile, Félix was reminding everyone that while he has plenty of talent, the other t-word (temperament) is sometimes missing: choosing to dribble inside his own half, he beat one opponent, lost the ball when his improbable spin move didn't work out, and then chased down and felled his opponent for yet another yellow card.

Ibrahimovic -- hugely influential to the point that he took the prematch news conference despite not having an official title beyond the one he gave himself ("I'm the boss") -- had said he expected his players to treat this game "like a final."

Until Theo's sending off, they largely did. And then, with one cravenly poor decision, Milan's European campaign unraveled.