Chelsea had been hot favourites to complete a remarkable debut season for manager Antonio Conte but was not at their clinical best as Arsenal, who finished fifth in the league, lifted the Cup for the third time in four seasons.
They have now won it a record 13 times while manager Arsene Wenger, who is yet to say whether he will be extending his 21-year reign, is now the most successful manager in the history of the competition with seven wins.
Chelsea made a woeful start and was behind after four minutes thanks to Alexis Sanchez’s controversial opener but when Diego Costa levelled in the 76th minute it seemed they would complete a memorable season.
Conte’s side had to play the last 20 minutes with 10 men after Victor Moses was dismissed following a second yellow card for diving.
Ramsey’s header in the 79th minute knocked the stuffing out of Conte’s side and Arsenal could even have extended their lead in the closing stages as Chelsea finally buckled.
Wenger, who failed to finish in the top four for the first time since taking charge in 1996, celebrated with his players in front of the massed red ranks of Arsenal fans at the end.
“We had an outstanding performance from the first minute onwards,” the 67-year-old Wenger said.
“This team has suffered. They’ve united and responded. I said last week this team will be in the championship with one or two good buys. They showed strength and unity and played spectacular football today.”
Underdogs Arsenal enjoyed a dream start although there was a huge debate about whether Sanchez’s effort should have stood.
When his initial attempt to chip the ball into Chelsea’s area was blocked, he appeared to knock the rebound forward with his arms before running through and shooting past Thibaut Courtois despite Ramsey standing in an offside position.
Confusion reigned as the goal was initially disallowed but after consulting with his assistant Gary Beswick who had raised his flag, referee Anthony Taylor awarded the goal.
Chelsea never properly recovered from that body blow and Arsenal could have been out of sight before halftime.
Mesut Ozil had a shot back-heeled off the line by Gary Cahill while Chelsea had an amazing escape when Danny Welbeck’s header thumped against the post and Ramsey bundled the ball back against the same upright.
Despite being all at sea Chelsea did threaten with Costa denied by a perfectly-timed tackle by Per Mertesacker who was making his first start for Arsenal for 13 months.
Arsenal keeper David Ospina also bravely denied Costa, receiving a blow to the head for his troubles.
Chelsea started the second half with more tempo and Footballer of the Year N’Golo Kante warmed Ospina’s fingers with a deflected drive from distance before Moses brought a fine save from Ospina after Costa played him in.
Chelsea were required to play the last 20 minutes a man down after referee Taylor’s second big call of the day, deciding that Moses had thrown himself to the floor under no obvious contact from Alex Oxlade-Chamberlain.
Just when it seemed their double hopes were slipping away, Costa equalised when his weakly-hit shot brushed off the excellent Mertesacker and past the diving Ospina.
But Arsenal had the last laugh when Chelsea’s defence went AWOL again, allowing Ramsey the freedom of the box to head substitute Olivier Giroud’s astute cut-back past Courtois.
The 68th Anniversary of the Founding of the People’s Republic of China.
— The Daily Mail - People's Daily