Chelsea's Mateo Kovacic in action with Eintracht Frankfurt's Sebastian Rode. Photo: Ralph Orlowski/Reuters
Maurizio Sarri may insist that the Premier League remains the priority for Chelsea, but it appears increasingly likely that his capricious first season in English football will finish in Baku.
Chelsea have moved a step closer towards the Europa League final after a spirited performance in Frankfurt which prevented Sarri from further scrutiny over his gamble to start with Eden Hazard on the bench.
Frankfurt's brilliant Serbian striker Luka Jovic had threatened to disrupt Chelsea's progress in this competition with his 26th goal of the season but they responded admirably, inspired by the outstanding Ruben Loftus-Cheek, to score a crucial away goal through Pedro.
Thursday's semi-final second leg at Stamford Bridge now represents a chance for Sarri to reach a second final in one season, so perhaps his campaign has not been the disaster his detractors would have you believe. Sarri certainly gave his critics ammunition by "resting" Hazard, but he will feel it was justified if Chelsea can beat Watford on Sunday to all but secure a top-four spot in the Premier League.
This was always going to be Chelsea's toughest proposition yet, after strolling to the semi-finals with 11 wins and a draw. Yet the decision to name Hazard among the subs titutes ppeared another of those mystifying calls from Sarri.
Before kick-off, Sarri insisted it was a risk worth taking. He said: "Hazard is on the bench because he played the last 10 matches in a row and secondly because usually he is really able to change the match from the bench. I think after 10 matches in a row he needs to rest. I don't want him to play for 90 minutes."
Chelsea's Olivier Giroud in action with Eintracht Frankfurt's Makoto Hasebe. Photo: Ralph Orlowski/Reuters
Eintracht were also protecting a formidable home record and in Jovic, on loan from Benfica, possess a player who is a summer target for a number of European heavyweights.
Eintracht were dangerous going forward and could have punished Chelsea in the early stages, finding spaces in the penalty area but unable to provide the final ball.
The visitors were struggling to repel the pressure and defender Andreas Christensen was booked for a rash challenge on Sebastian Rode, with the opening goal seeming inevitable.
The breakthrough came in the 23rd minute and it came from Jovic. Filip Kostic swung over a cross and Jovic was unmarked to direct a diving header into the corner past Kepa Arrizabalaga.
Chelsea responded with Pedro driving a 20-yard shot narrowly wide, and finally they started to apply some pressure of their own. Loftus-Cheek was proving influential in midfield as the game opened up and almost made an equaliser out of nothing, going past three Eintracht defenders before dragging the ball inches past the bottom corner.
Yet Chelsea did level it up on the stroke of half-time to temporarily silence the boisterous home support. Loftus-Cheek was again involved, cleverly picking out Pedro in the box, with the Spaniard producing a clinical finish.
It felt like a crucial moment, and it damaged the confidence and swagger of Eintracht, who were now second best.
Eintracht Frankfurt's Luka Jovic in action with Chelsea's Andreas Christensen and N'Golo Kante. Photo: Kai Pfaffenbach/Reuters
Loftus-Cheek started and nearly finished another swift counter-attack in the 55th minute, breaking forward and releasing Pedro in the area, then taking the ball back and lifting a shot over the crossbar.
Two minutes later Willian was played in by Loftus-Cheek but delayed too long and drove the ball straight at Kevin Trapp. The Eintracht goalkeeper then tipped a David Luiz free-kick onto the bar.
Sarri's gamble on resting Hazard was now appearing vindicated, and the Belgian was introduced in the 62nd minute at a time when Chelsea were dominating.
They had a further chance, with Luiz heading straight at Trapp from a decent position after a Hazard free-kick. (© Daily Telegraph, London)