Arsenal will face Chelsea in the English FA Cup final after the Gunners qualified for their 20th final by defeating Manchester City 2-1in the semi-final on Sunday at Wembley.
The Gunners also reached their third FA Cup final in four seasons, winning the trophy in 2013/2014 and 2014/2015.
Alexis Sanchez scored the winner 11 minutes into extra-time.
Sergio Aguero gave Manchester City the lead in the 62nd minute but Nacho Monreal’s right-foot finish from close range beat Claudio Bravo for the Gunners equaliser.
Nigeria forward Kelechi Iheanacho replaced Raheem Sterling in the 105th minute of the encounter while Super Eagles winger Alex Iwobi was an unused substitute. It could have been Iwobi’s ninth FA cup appearance for the Gunners.
Manchester City started the encounter brightly with Jesus Navas and Kevin De Bruyne making attempts on goal.
Oliver Giroud directed his header straight at Claudio Bravo in the 15th minute. David Silva had the best chance in the first half with his goal-bound header tipped off for a corner in the 17th minute.
City had a penalty claim in the 30th minute when Sergio Aguero was fouled inside the box under a challenge from Oxlade-Chamberlain, but referee Craig Pawson waved away his penalty appeal.
The first half ended goalless with few shots on target.
In the 61st minute Arsenal gave away possession through Aaron Ramsey to Yaya Toure who found Aguero with a delightful pass and the striker dinked the ball over the Petr Cech in goal for Arsenal.
Fenandinho also crashed the upright with a thumping header as the game drew closer to extra time.