Chelsea took a big step towards a Europa League semi-final place as a late Marcos Alonso header was enough to give a below par Blues side the win in their first leg tie at Slavia Prague on Thursday night.
The hosts had the better of a quiet first half, but it was the Blues who came closest to breaking the deadlock through Willian's thunderous strike which crashed off the crossbar.
Eden Hazard was brought on just after the interval to try and bring a dismal game to life, and his arrival quickly raised the tempo, with Antonio Rudiger's volley forcing a smart save, before Willian dragged a good opportunity just wide.
Chelsea's winner came in the 85th minute when a wonderful Willian cross was powerfully headed home by Alonso to give the Blues their crucial away goal.
Here's our breakdown of this one.
Key Talking Point
Chelsea got the job done tonight, but at their worst under Sarri, the Blues look like 11 players who are on totally different pages, and quite frankly appear as though they could not care less.
Their first half performance in particular was a chief example of that sort of display. Their opponents pressed them extremely high right from the off and they couldn't handle it, clearly having no plan b despite their passing being so poor.
Yes, Slavia Prague proved they are no mugs by getting passed Sevilla in the previous round, but the starting midfield three were virtually anonymous, meaning the front line had to live off scraps all evening.
Substitutes: Hazard (6), Kante (6), Loftus Cheek (5)
STAR MAN: Antonio Rudiger
At a time when it looked as if all those around him were panicking, the big German stayed calm on the ball ans relentlessly stopped any sniff of a Slavia attack.
Rudiger displayed maturity and even had a couple of chances to break the deadlock, showing his determination to make things happen for the Blues, unlike a number of his teammates.
His strength, pace and ability on the ball are to be admired, and he is fine defender who stepped up big time to help Chelsea navigate a potentially difficult evening in the Czech Republic.
Chelsea continue their quest for a top four Premier League finish when travel to leaders Liverpool on Sunday, before the return leg against Slavia next Thursday.
The Blues host strugglers Burnley the following Monday, before a trip to Old Trafford in a massive clash between two Champions League chasing sides against Manchester United on the 28th.
Slavia Prague will look to maintain their lead in the Czech first division when they host city rivals Sparta on Sunday afternoon.