Last weekend, despite a fine performance against Leeds United, he held his hands up and admitted he had played everyone onside for the winning goal.
Last Tuesday he celebrated his first international cap after turning out for England Under-21s against Spain.
But it was back to the blues on Saturday as a somewhat nervous first half display at Derby County ended with him upending Malcolm Christie to hand the Rams a second goal from the penalty spot. He was then hauled off at half-time.
Boss George Graham talked afterwards about the ‘learning curve’ his youngsters are going through and Thelwell, just 20, quickly learned that any mistake in the Premiership was jumped on both at the time and in the weekend’s media afterwards.
George also talked about Thelwell’s great attitude and it is certainly to his credit that he can talk us through his torrid time.
“I was very disappointed with my first half performance,” he admitted. “It didn’t go well for me at all.
“The penalty was a bit of a rash challenge and it was my mistake in the first place, I should have cleared it, but those things happen and I gave the penalty away and my confidence was low after that.
“It wasn’t the best of games but hopefully I’ll pick up, work hard and try to come back for the next game.
“That’s football I suppose. One minute I’m in the England under-21 squad and making my debut, I was happy about that, then Saturday it’s back to the Premiership and I didn’t play so well.
“I’ve just got to pick myself up and push on again, try to forget Saturday, it’s gone, and get on with it.”
Thelwell was noticeably last off the training pitch at Spurs Lodge on Monday after a lengthy head-to-head with reserve team boss Chris Hughton.
He added: “I’ve looked at the game again, seen where I went wrong and I’ve got to put those things right in training. I’m still young. You don’t want to make mistakes but you have to learn from it.
“I’ve played 12 games now in the first team and that is good experience for me. I have to forget Saturday and pick myself up again.”
Alton Thelwell has learnt a harsh lesson about the fortunes of football in a rollercoaster seven days.