A dominant display in both boxes temporarily relieved Frank Lampard's squad of recent criticism, as Olivier Giroud and Mason Mount struck while Harry Maguire's own goal seriously rubbed salt into the wound of Man United boss Ole Gunnar Solskjaer.
Bruno Fernandes stepped up to score a late penalty for United, but that was the only consolation for the well-beaten Red Devils.
A defensive performance of total contrast when considering the Blues' recent Premier League duels against Crystal Palace and Sheffield United. Frank Lampard's two wing-backs, Reece James and Marcos Alonso, pressed with great intensity to match the work rate of their teammates.
Given Chelsea's high-pressing approach in this afternoon's cup semifinal, fouls were always likely to be conceded. And on a strong day, United could have easily converted more than once from ideally placed free kicks on the perimeter of the Chelsea penalty area. The only fault in what was a fine performance.
Manager rating out of 10
9 -- A brilliant tactical approach by Frank Lampard to this FA Cup semifinal must be praised amid doubts concerning Chelsea's defensive performances in the Premier League of late. A combination of small tweaks went a long way in turning around Chelsea's fortunes, as the likes of James and Alonso pressed forward excellently while Mount's lingering on the chalk helped transitional play improve tenfold.
Player ratings (1-10; 10 = best, players introduced after 70 minutes get no rating)
GK Willy Caballero, 7 -- Retained his starting XI spot from last month's quarter-final win over Leicester and delivered a solid if unspectacular performance. His distribution was fine, while shot-stopping was at a premium as a sub-standard United struggled to pierce Chelsea's back three.
DF Cesar Azpilicueta, 8 -- Excellent calmness in possession earned Azpilicueta a deserved assist at the conclusion of the opening half in a move that reflected earlier attempts to open the scoring down the left side.
DF Kurt Zouma, 8 -- A regular threat in United's penalty area, Zouma backed up his efforts up front with a fine defensive performance that was clearly aided by Lampard's decision to play three at the back. Conceded a few cheap fouls, but that is to be expected when considering Chelsea's high tempo.
DF Antonio Rudiger, 8 -- Like defensive teammates Azpilicueta and Zouma, Rudiger was extremely well focused in defence and acted promptly to cut out any United counter-attacks. Marcus Rashford was controlled well on the right also to stem the Red Devils' forward movement.
MF Reece James, 9 -- James' license to push forward granted Chelsea a new lease on life up front. But this aggressive tactic of Lampard's did not impede the 20-year-old's ability to quickly backtrack and defend when United did rarely occupy possession. A fine defensive performance which can be built on.
MF Jorginho, 8 -- The resurgent form of Bruno Fernandes was always going to be tricky to control, but Jorginho helped limit the effectiveness of United's key man brilliantly with a fine midfield performance which took pressure off of the defenders behind him.
MF Mateo Kovacic, 8 -- Won possession well in midfield against a poor United XI that never moulded together throughout the 90 minutes of play. Quick-thinking play while under pressure in particular stood out as Kovacic's' strong point.
MF Marcos Alonso, 8 -- Strong work ethic and great intensity both in and out of possession allowed Alonso to control his area of play and breakdown any time United looked poised to mount an attacking challenge.
FW Willian, 9 -- His impressive work rate acted as a catalyst for Chelsea to press forward with great confidence. Would have done Willian no harm to occasionally look up at the running options of Mount and Giroud but overall it was an excellent performance full of class from the Brazilian.
FW Olivier Giroud, 9 -- Man marked by Harry Maguire throughout, Giroud played with a great tempo and put his body on the line to win a number of long balls forward with his head. A typical poachers' finish added to his impressive FA Cup tally.
FW Mason Mount, 8 -- Wasn't afraid to try his luck from distance, and twice tested David De Gea before scoring in fortuitous circumstances after half-time thanks to the United keeper fluffing his lines. Hs great pace and energy complimented the work of Willian and Giroud.
MF Pedro, N/R -- The veteran got a run out in what will be one of his final appearances with the Blues.