However, Lampard was sacked in January and replaced by German manager Thomas Tuchel, who guided the club to European glory, as on 29 May, Chelsea defeated fellow English side Manchester City in the Champions League final, their second title in the competition, and their first since 2012.

Chelsea played their first game of the new Premier League season on 14 September 2020, travelling to Brighton & Hove Albion and earning a 3–1 away victory, courtesy of goals from Jorginho, Kurt Zouma and Reece James.

Chelsea were 3–0 down at half-time, but goals from Mason Mount, Callum Hudson-Odoi, and Tammy Abraham in stoppage-time managed to seal a draw as the match ended 3–3.

Timo Werner scored his first Chelsea goal to put the Blues ahead, but Erik Lamela managed to equalise in the second half.

[11][12] Chelsea then defeated Krasnodar 4–0 away in the Champions League, with Callum Hudson-Odoi, Timo Werner, Hakim Ziyech, and Christian Pulisic all on target for the Blues.

[15][16][17][18] Chelsea begun November with a 3–0 home victory over Rennes in the Champions League, with the goals coming from two Timo Werner penalties and a Tammy Abraham strike.

[28] On December 5, they welcomed bitter rivals Leeds United to Stamford Bridge, in Chelsea's first home game with 2,000 fans in attendance.

Tammy Abraham scored a consolation goal in the 85th minute, and Jorginho had a penalty saved in added time by Bernd Leno, to ensure no comeback was to happen for the Blues, in a humiliating 3–1 defeat.

[34] Chelsea closed out 2020 with a 1–1 home draw against Aston Villa, with Olivier Giroud and Anwar El Ghazi scoring the only goals of the game.

Chelsea went on to lose this match 2–0, with first-half goals from Wilfred Ndidi and James Maddison piling more misery on the Blues' bad run of form.

[43] Alonso's strike against the Clarets earned him a nomination for the Premier League Goal of the Month award, eventually won by Liverpool's Mohamed Salah.

[44][45] Chelsea opened February with three consecutive away victories at Tottenham Hotspur and Sheffield United in the league, and Barnsley in the FA Cup.

[49] Chelsea then took the trip to St Mary's Stadium to take on Southampton on 20 February, who had lost their last six Premier League matches in a row, including a 9–0 defeat at Manchester United.

[51] Chelsea returned to Premier League action on 28 February, playing out a dull goalless stalemate against Manchester United at Stamford Bridge.

Chelsea defeated the Reds 1–0, with a superb Mason Mount strike in the 42nd minute condemning Liverpool to their fifth home loss in a row, and Tuchel extending his unbeaten run to 10 games.

[57] Chelsea then played the second leg of their Champions League round of 16 tie against Atlético Madrid, this time at home, with the Blues heading into the game with a 1–0 advantage and a away goal.

[58] The victory also meant that Tuchel became the first Chelsea manager to go unbeaten in his first 13 matches in charge of the club, surpassing the previous record of 12 held by Luiz Felipe Scolari.

Chelsea were defeated 1–0 thanks to a late Mehdi Taremi overhead kick, but did enough to make it through to the Champions League semi-finals, winning 2–1 on aggregate.

[76] Their win set up an all-English affair after Manchester City had secured their maiden appearance in the final the day before, defeating Paris Saint-Germain over two legs.

Hakim Ziyech scored the equaliser for the Blues in the 63rd minute, before a stoppage-time goal from Marcos Alonso saw Chelsea run out 2–1 winners, as Thomas Tuchel made it two consecutive victories against Pep Guardiola.

Chelsea were shockingly defeated 1–0, with a poor back pass from Jorginho allowing Emile Smith Rowe to score the winner for Arsenal, with Christian Pulisic also having a goal disallowed by VAR due to a handball.

Chelsea would go on to lose 2–1, but still finished fourth and secured their place in next season's Champions League, as elsewhere, Leicester City lost to Tottenham Hotspur.

It was the third time in Chelsea's 116-year history that they had competed in the Champions League final, losing against Manchester United in 2008 and defeating Bayern Munich in 2012.

New signing, Kai Havertz, then latched on to Mason Mount's pass after a clever Abraham dummy and slid left-footed effort into the bottom corner to open his Chelsea account.

[205] Ross Barkley made it three after the break before Abraham's neat flick teed Havertz up for a simple finish inside the area.

[205] The fourth round draw was conducted on 17 September 2020 by Laura Woods and Lee Hendrie live on Sky Sports; Chelsea were handed an away game against Tottenham Hotspur, led by former manager José Mourinho.

[207] However, Erik Lamela would equalize for Tottenham with six minutes to go and the hosts would go on to win in the penalty shoot-out after a solitary miss from Chelsea midfielder Mason Mount.

Chelsea moved on to the quarter-finals after a 2–0 second-leg win, with a goal in each half from Hakim Ziyech and Emerson, and were drawn against FC Porto.

Christian Pulisic gave Chelsea the lead before Karim Benzema equalized for the home side, the match ended in a 1–1 draw.

In the final at the Estádio do Dragão, Chelsea would emerge victorious against Manchester City 1–0 with a goal from Kai Havertz sealing their first Champions League title since the 2011–12 campaign.