Our Uruguayan star clashed heads with Trevor Sinclair as he met Simon Davies' cross in the 48th minute at Upton Park. His effort was pushed onto the post by David James and Les Ferdinand followed up to slam the ball home. It was the only goal of the game.
The midfielder was so dazed that he spent nearly five minutes standing in the West Ham six yard box before he could be persuaded to leave the field.
Boss Glenn Hoddle explained: "Gus has got deep concussion. He is in hospital and he will have some scans done. He was totally out of it and was complaining to David Elleray that we should have been awarded a corner - he didn't even realise we'd scored.
"It was very brave of Gus to go in for that challenge, but that is his trademark. He went in with venom and if Sinclair hadn't made the challenge he might have scored himself.''
Listen to Glenn's post-match thoughts in full by clicking here or onto the audio link on the right
Gustavo Poyet is likely to spend tonight in hospital suffering from concussion after bravely setting up our winner at West Ham.