By Phil McNulty, BBC Chief football writer

When Chelsea owner Roman Abramovich proved no-one’s history at the club could shield them from his ruthless pursuit of success by sacking the iconic figure of manager Frank Lampard in January, he was following a well-worn formula.

Abramovich has a habit of acting brutally but with ultimately successful outcomes – so it was no surprise that as Lampard went out of one door at Stamford Bridge, in came the experienced, proven managerial expertise of Thomas Tuchel.

Chelsea were ninth in the Premier League when Lampard was dismissed, the statement confirming his departure insisting the club was “without any path to sustained improvement”.

Tuchel has had the required transformative effect. Their FA Cup semi-final win over Manchester City, following on from the Champions League quarter-final victory over Porto, certainly qualifies as sustained improvement after Lampard’s latter-day struggles.

Abramovich’s most spectacularly successful changing of the Chelsea guard came in March 2012, when he sacked Andre Villas-Boas after less than a year in charge and replaced him with interim Roberto di Matteo, who promptly went on to win the FA Cup and the Champions League in a quite remarkable series of events.

It was not a long-term success and Di Matteo lasted only a matter of months after his permanent appointment and those great triumphs – but could Tuchel be about to reward another Abramovich intervention in similarly successful fashion?

Tuchel carries more of a sense of permanency, if that word can ever be used about any manager at Stamford Bridge, than Di Matteo ever did and watching Chelsea subdue then overcome Manchester City so impressively at Wembley suggests a similar double is not beyond them.

Chelsea will be favourites in the FA Cup final against Leicester City or Southampton and while Real Madrid showed their enduring class and resilience by beating Liverpool over two legs in the Champions League, Tuchel has every right to be cautiously confident against Zinedine Zidane’s side.

This knockout tie against Manchester City, won by Hakim Ziyech’s goal, could yet be a rehearsal for the Champions League final in Istanbul on 29 May, with the Premier League champions-elect playing Tuchel’s old club PSG in their semi-final.

If that is the case, Chelsea can take huge confidence in the way their manager planned for this game and the manner in which his players carried out the strategy of closing City down and using the pace of Ziyech and Timo Werner to emerge as the better side and deserving victors.

Tuchel possesses the sort of authority and track record from his career at the likes of Borussia Dortmund and PSG to command the instant respect of his players and his record at Chelsea so far acts as the proof.

He is the first German manager to reach the FA Cup final and since his first game in charge in January, Chelsea have kept 14 clean sheets in 19 games, more than any other side in the top five European leagues. It is also one more than in Lampard’s 29 games in charge this season.

Tuchel had failed to beat Guardiola in five previous attempts as a manager – two at Mainz and three at Borussia Dortmund – so everything about this win would have tasted sweet.

One look at his touchline demeanour confirms his demanding approach – a minor error from Werner bringing a full-on hop, skip and jump of fury from his manager.

Tuchel has organised Chelsea superbly at the back, City barely having a chance, while N’Golo Kante and Jorginho provide a formidable obstacle as well as creation in midfield, along with the increasingly mature and outstanding Mason Mount.

Werner’s end product continues to be erratic but he unselfishly set up Ziyech’s winner and those inclined to criticise his contribution since his £47.5m move from RB Leipzig may note he has been directly involved in 19 goals for Chelsea this season – 10 of his own and nine assists – which is three more than any other player at the club.

Kai Havertz only came on as a late substitute but the young German is also showing signs he is settling at Chelsea after problems with illness and form to suggest he will become a prize asset.

The main man at the moment, however, is Tuchel.

He has shown tactical expertise, restoring the influential Antonio Rudiger in defence and putting the superb Kante at the heart of his plans, while using his experience to get victories against his celebrated peers such as Jose Mourinho at Spurs, Liverpool’s Jurgen Klopp, Everton manager Carlo Ancelotti and now finally Guardiola.

Confidence, momentum and form are priceless commodities at this stage of the season and as Chelsea and Tuchel set their sights on the FA Cup final, the Champions League semi-final and a place in the Premier League top four, they currently possess all three in abundance.

Originally published at BBC