VILLARREAL'S Matteo Gabbia was knocked out cold and rushed to hospital after a freak collision with a team-mate against Rennes.
The defender's sickening injury overshadowed a contentious climax to a dramatic 3-2 Europa League victory for the Spanish group winners.
Gabbia's head caught the knee of Villarreal skipper Raul Albiol as he stooped to nod the ball away.
The face of the loan centre-back rocked back worryingly and he collapsed to the floor with his arms sinking over his head.
The 24-year-old was carried off on a stretcher and taken to a French hospital.
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The former Italy Under-21 star was expected to be kept in for tests - rather than return to Spain with the rest of the Villarreal squad.
The LaLiga club borrowed Gabbia from AC Milan for the season.
But reports in Italy suggest the Serie A giants have been keen to negotiate an early end to the deal - due to a mounting injury list.
Gabbia's misfortune diverted attention from a dramatic tie with a hotly-debated finale.
Rennes needed a point to overhaul Villarreal and go through to the last 16 as group top dogs.
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And only a last-gasp VAR decision that baffled viewers denied the hosts a last-gasp equaliser.
Gerard Moreno and Ilias Akhomach had put Villarreal ahead in each half, with Lorenz Assignon and Luydovic Blas levelling.
Dani Parejo then put the Spaniards back in front at 3-2 on 80 minutes.
But Assignon was convinced he had earned Rennes the point they wanted at the death when he eventually tucked away a rebound from a free-kick.
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Video replays ruled it out, however - to the bemusement of TNT commentators as much as armchair observers.
Offside was thought to be the only possibility - but Assignon was shown to be onside.
It was later revealed the goal was erased because Enzo Le Fee had been first to touch the ball after his initial free-kick cannoned off the bar.
Once the ball is active, a free-kick taker can't touch the ball before any other player has.