Reading 1 Arsenal 2 (aet)

It must be said, Arsenal do not bear the tag of favourites with comfort when they play at Wembley Stadium.

For the second year in a row, the Gunners required extra time to squeeze into the FA Cup final by the skin of their teeth against Championship opposition.

And, on this occasion Arsene Wenger’s side were indebted to an extra-time howler by Reading goalkeeper Adam Federici, who allowed an innocuous effort from Alexis Sanchez to creep under his body and settle the tie.

Sanchez had fired the Gunners in front just before half-time, but Garath McCleary’s equaliser brought the Berkshire side level – and they gave as good as they got against the cup holders.

Arsenal had a good opportunity to open the scoring in the seventh minute, when Per Mertesacker stole in to meet a near-post corner with a header that was blocked on the line by Federici.

Mesut Ozil and Santi Cazorla also went close, but for the most part Reading held their own, stifling the Gunners in midfield and aiming to hit them on the counter-attack.

Jordan Obita’s left-foot drive was comfortably gathered by Wojciech Szczesny, while Nathaniel Chalobah struck a crisp volley that spun off Mertesacker and flew behind.

But generally there were few clear chances for either side, and it came somewhat out of the blue when Arsenal broke the deadlock six minutes before the break.

Ozil’s measured pass picked out Sanchez inside the Royals’ penalty area and the Chilean evaded McCleary’s challenge before tucking his finish under Federici.

Reading failed to pick up Mertesacker at another set-piece soon after the restart, but the Gunners skipper’s header drifted wide of the post – and it was the Championship side who began to apply some pressure.

They drew level in the 54th minute when Pavel Pogrebnyak wriggled clear and squirted a cross to the far post, where McCleary stretched to hit a volley that deflected off Kieran Gibbs and, although Szczesny pawed it the ball, he could not prevent it crossing the line.

The Gunners looked crushed by that equaliser and Reading had a decent penalty shout turned down soon afterwards when Obita’s cross struck the outstretched hand of Mathieu Debuchy.

Then Jamie Mackie, burrowing down the left-hand side, set up Daniel Williams, but the midfielder miscued his volley and the scores remained level.

With Mertesacker limping off, his replacement Gabriel Paulista could have restored Arsenal’s lead twice from headers – one sailing over the bar and the other clawed away by Federici.

As the game opened up, there were good opportunities for both sides in the last 10 minutes of normal time, with Federici foiling Aaron Ramsey, who then bundled the rebound against the post.

At the other end, Pogrebnyak burst clear but, with Mackie in space to his left, opted to shoot and could not find the finish to beat Szczesny.

There were few incidents of note in extra time until the end of the first period, when Federici tipped Ramsey’s drive over and then Pogrebnyak, storming clear at the other end, was halted by Laurent Koscielny’s challenge.

But Sanchez doubled his tally right on the stroke of the interval, cutting inside Chris Gunter and firing a routine shot that squirmed under the body of Federici, despite the keeper’s desperate attempt to scoop the ball back.

Substitute Olivier Giroud fired into the side netting in the second half, but there were no further goals and a relieved Arsenal side scraped through to defend their trophy in next month’s final.

Arsenal: Szczesny; Debuchy, Mertesacker (Gabriel 63), Koscielny, Gibbs; Cazorla, Coquelin (Walcott 101); Ramsey, Ozil, Sanchez; Welbeck (Giroud 72).