LONDON — Alexis Sanchez sent Arsenal back into the FA Cup final, scoring his second goal of the semifinal in extra time Saturday to secure a 2-1 win over Reading at Wembley.
Sanchez decided the game for the defending champions in the 105th minute thanks to a goalkeeping blunder, as he cut inside from the left and hit a low shot through traffic that Adam Federici spilled between his legs.
It ended the resistance of the second-tier club, which fought back from Sanchez's 40th-minute opener but couldn't muster a second comeback in the final 15 minutes.
Garath McCleary equalized in the 54th with a goal that was confirmed by goal-line technology when Wojciech Szczesny couldn't keep out his low shot.
Arsenal will face either Liverpool or Aston Villa in the May 30 final as it looks for its 12th FA Cup title.
It was another difficult semifinal for Arsenal, though, which needed penalties to overcome Wigan at this stage last year on its way to ending a nine-year trophy drought by beating Hull in the final.
"They really wanted it," Arsenal manager Arsene Wenger said of Reading. "They were ready to die on the pitch today to go to this final. You have to congratulate them for the effort they put in."
Riding a 10-game winning streak in all competitions, the Gunners were the heavy favorites and dominated possession from the start, continually probing the Reading defense. But Wenger's team looked far from its most fluent, and its buildup play was slow and without imagination, lacking incisive passes.
"What was missing was a bit of speed of combination in the final third and sharpness in the final third," Wenger said. "But overall, I believe the spirit and concentration was there."
They finally broke through when Mesut Ozil took a more direct route, lofting a perfectly weighted pass into the area toward Sanchez, who downed the ball on his chest, held off a defender and calmly slotted a low shot past Federici.
Then Arsenal was punished for a tentative start to the second half. Pavel Pogrebnyak set up Reading's equalizer when he broke down the left side and floated a pass across the goalmouth that fell to McCleary. His shot took a slight deflection off Kieran Gibbs and went past the diving Szczesny, who got his hand on the ball but couldn't keep it from crossing the line.
Arsenal had several chances to retake the lead but Ozil fired well high from just outside the area and Aaron Ramsey hit the post from his own rebound after his initial shot was blocked by Federici.
Defender Gabriel, who came on for the injured Per Mertesacker, forced another good one-handed save from Federici with a header from a corner.
Sanchez bailed out Arsenal, like so often this season. With the extra time interval looming, he took another pass from Ozil and sent in a speculative shot through three defenders that Federici should have easily kept out. But it went between his legs and slid slowly into the net, ensuring a return to Wembley for Arsenal next month.
"He looked to struggle a bit to get into the game," Wenger said of Sanchez. "But he has that stubborn resilience, and that is the potential that allows him to always to create something special."
Reading manager Steve Clarke said he couldn't have asked for more from his team.
"It was a really good performance," Clarke said. "I feel for the players, they gave everything, feel for the supporters, they gave everything. It should have been a good afternoon for us but sometimes in football you do not get reward for such a good performance."