Goals from Olivier Giroud, Mason Mount and an own goal from Harry Maguire, meant that Frank Lampard's side will be playing Arsenal in the FA Cup final.
There were changes to the team as the Blues had one eye on Wednesday's match with champions Liverpool. As well as that, last night saw a change in formation.
In what was a brilliant display from the Blues, here are five things we learnt against Manchester United.
1) The divine rise of Mason Mount
Mason Mount was pitch-perfect last night. His performance showed why he's one for the future. Even after the game, Mount received the plaudits from many across the footballing world.
Pundits were thrilled with his work rate and commitment and even said that he is higher than Jack Grealish and James Maddison in the England pecking order.
We saw him dominate the midfield, he was a real threat going forward, and the goal was the icing on the cake for Mount. Right from the start, the Englishman was flawless in what was a brilliant game by the youngster.
2) The big man is firing
It's fair to say that Olivier Giroud has received a lot of praise since signing for Chelsea. Yesterday, however, he was as instrumental as he has ever been in leading the line.
Following the restart of football, Giroud has established himself as the leading frontman in Chelsea's attack, and he has well and truly stepped up to the task.
Giroud scored yet again in the victory over United, and he was a real threat going forward. His hold-up and link-up play were second to none, and this Chelsea side has managed to complement Giroud, recently, and play to his strengths. The Frenchman had a great game last night, causing constant havoc for United's defence.
3) The Croat sensation in the heart of midfield
Mateo Kovacic has been a real standout player this season. He has arguably been Chelsea's best player at times during the campaign. When the Blues have struggled in a game, he would often be the player to dictate the game and drive the team forward.
The Croatian ran the show yesterday. Like Mount, Kovacic bossed the midfield. He was always looking to quickly turn defence into attack and get the team going forward.
Kovacic carries the ball very well and elegantly and is always looking to progress forward. The man is key in Chelsea's midfield and has proven he can be the one to spark a positive performance no matter the circumstances.
4) Reece James: One for the future
Reece James has impressed a lot of Chelsea fans this year, in what has been his debut season in the Premier League. Although, fans have questioned his defensive contributions and whether or not he's consistent at the back during this campaign.
However, James stepped up last night. He seems to have matured well and caused a lot of problems for United's backline. At the back, he was one of the best defenders on the pitch yesterday.
He slotted in well in the wing-back role and proved that even though he still has areas to work on, he can become a top player.
5) A Frank Lampard masterclass
The Blues faithful have to give credit to 'Super Frank.' His tactics were spot on, in what was a wonderful team performance from the Blues.
His team set-up was brilliant, man for man the whole team competed with United. When the wing-backs pushed forward, the centre backs and the midfielders would fill in for the pressing wing-backs.
The 3-4-3 and even the 3-5-2 system compliments Lampard’s style of play, and last night showed that. Right from the get-go, the players knew their job and knew what they had to do to compete with a dangerous United team. Judging by yesterday's performance, the manager deserves a lot of praise in what could turn out to be a stand out first season in charge.