Arsene Wenger was delighted as Danny Welbeck struck a second-half winner to put Arsenal into the semi-finals of the FA Cup with a 2-1 victory over his former club Manchester United.
The Gunners took the lead midway through the first half as Alex Oxlade-Chamberlain weaved his way through the United defence before teeing up Nacho Monreal to coolly slot his close-range shot past a diving David de Gea and into the bottom corner.
It did not take long for the hosts to level matters and Wayne Rooney did the damage as he directed Angel di Maria's beautiful cross into the back of the net via a well-timed header.
Welbeck handed Arsenal the lead for the second time as he beat De Gea to the ball just outside the box and tapped into an empty net just after the hour mark.
Wenger was full of praise for Welbeck, who left his boyhood club for north London last summer.
He said: "I believe he is just happy to score. He worked very hard today and he was rewarded by a good goal."
Di Maria received two bookings in quick succession as he was first shown a yellow card for diving and then was sent off after grabbing at referee Michael Oliver's shoulder in protest with just under 15 minutes left.
Arsenal were drawn against Bradford or Reading in the last four and Wenger added: "We have played Bradford before, we know about that, but let's enjoy tonight. I feel we played a good game from the start and deserved to win."
Aston Villa will play the winners of the Blackburn Rovers v Liverpool replay in the other semi-final tie.