For the first time since Thomas Tuchel took the Chelsea job, his side suffered a defeat when West Bromwich Albion fired five goals past them, and the result has seen the Blues’ sense of invincibility disappear.

Ever since Frank Lampard’s dismissal, Tuchel has had his team playing at a level that surprised many people, and a comfortable aggregate victory over Atletico Madrid had given the Blues a fighting chance in the Champions League.

Being drawn with Porto in the Champions League quarter-final was another stroke of good fortune, especially with the winner of that time in the beneficial side of the draw, facing the winner of Real Madrid and Liverpool, rather than one of Manchester City, PSG or Bayern Munich.

However, the defensive brittleness shown against West Brom has given credence to the belief that Porto can actually get at the Blues’ defensive line, in much the same way they did to Juventus over two matches in the round of 16.

“The red card came, and after that we were unable to cope with the situation, I don’t know why but it was like this,” Tuchel admitted in his post-match interview.

“We gave away two very easy goals before half-time, but after the red card whatever could go wrong did go wrong.

“It’s a good wake-up call for all of us, myself included.”

Is this just a blip?
The problem for Chelsea now is they have to bounce back right away. Everything has looked so easy since Tuchel took charge, but now they are facing a difficult moment for the first time under his stewardship.

Whilst the Champions League wasn’t seen as a priority target when Lampard left, it has now become seriously important for Chelsea. In the form they were in prior to Saturday’s lunchtime kick-off, they were favourites to reach the final on their side of the draw.

That hasn’t necessarily changed, but they will have to get a positive result against the Portuguese champions, otherwise their season could unravel in the same way their game against West Brom unravelled.

Dressing room discord?
Chelsea have always struggled with big personalities in their dressing room, yet one worrying story to emerge since Saturday is a bust-up between Antonio Rudiger and backup goalkeeper, Kepa Arrizabalaga.

It’s understood that the pair have since reconciled, but this is the last thing Tuchel wants to develop ahead of such a big European tie.