In spite of coming from behind twice on Thursday evening, Aston Villa slipped to a 3-2 defeat in the Europa Conference League game in Poland.
The defeat puts pressure on Emery’s side from the very outset as it narrows down the Premier League side’s margin for error.
Thompson on his part believes that the loss is a massive wake-up call for Emery’s team and comes at a perfect time.
Being the big dogs in the competition, the 63-year-old insists that Aston Villa have to do their job properly and looking at his team’s performance, the veteran believes that Emery will decide against taking any more chances.
“Unai Emery has done a fabulous job so far but all of a sudden we find ourselves in European competition and this is a massive wake-up call”, Thompson said on BBC Radio WM.
“It’s the perfect time for it to happen.
“We can’t make too many more mistakes in this competition now. We have to make sure we win the next game and build from there.
“Emery will be shocked about the way this has gone but there was a hint of smugness about the way Villa played.
“They felt they’d always get themselves back into the game.
“They are the big dogs and you have to go and do the job properly.
“There was a purpose about what Legia Warsaw wanted to do. Aston Villa just wanted to keep the ball and didn’t really look forward too often.
“Unai made changes tonight because he felt that side was still strong enough to get something.
“He’s been proved wrong and he will now be looking at this and thinking ‘we can’t afford to take any more chances.
“We’ve got five games to go, we’ve got to try and win the next three’.”
The loss has pushed Aston Villa to the bottom of Group E with Bosnian side Zrinjski Mostar occupying top spot following their 4-3 win over AZ Alkmaar.
