Thomas Tuchel has turned Chelsea from a squad lacking direction into FA Cup and Champions League finalists, and all in 14 weeks.
Here, the PA news agency examines five key changes the Blues' German boss has made at Stamford Bridge.
Tightened up the defence
Tuchel's Chelsea have racked up a staggering 19 clean sheets since he took the helm in late January. The well-drilled defensive system has helped the Blues stymie opponents at almost every turn. And with every shut-out Chelsea's players have visibly grown in confidence and assurance.
Created a definitive style
The former Paris St Germain boss has not only changed the Blues' main formation, he has also delineated individual and collective roles so clearly as to leave his players with no doubts about what to do in any situation. Tuchel's 3-4-3 at Chelsea has taken the best bits of his predecessors Antonio Conte and Maurizio Sarri, and moulded those with his own ideas and also other elements that suit the players at his disposal. The results have been hugely impressive.
Maximised the impact of N'Golo Kante
World Cup-winning France midfielder Kante had been struggling with on-off hamstring injuries for months before Tuchel's arrival. The former Leicester star had also been operating in a more advanced role under Frank Lampard. Tuchel's desire for two holding midfielders – double sixes in his vernacular – has played entirely to Kante's ball-winning strengths however. Restoring Kante to the midfield's base has allowed the all-action star to scale even greater heights, where possible. The 30-year-old's man-of-the-match awards in both semi-final legs against Real Madrid stands as positive proof of that rich vein of form.
United a disparate squad
One of Tuchel's first acts was to bring Marcos Alonso in from the cold. The Spain left-back had been frozen out by Lampard, with his future chances looking bleak under the former manager. Tuchel pitched Alonso straight back into the first team from the moment he arrived in west London however. And the dividends have been huge. Ben Chilwell has since fought his way back into the starting XI, but Alonso retains an important role. And Tuchel's squad rotation and man management has helped him keep favour with the bulk of a talented and large line-up.
Lifted all the personal pressure
Tuchel's first major masterstroke came in deftly dismissing questions about his long-term future. An 18-month contract quite clearly offers no security for the astute German. But rather than fret, or avoid the issue, he confronted it directly. And by bluntly admitting that a long-term contract would not save him from the sack, he immediately removed a huge amount of pressure. Any Chelsea manager has to earn the right to multiple years at the helm, as Lampard discovered the hard way. Deliver on the field, and Chelsea's board will return the favour off it.