Two goals from England international Alex Oxlade-Chamberlain, one in each half, ensured Reading's EFL Cup run would end at the Emirates this evening.
Jaap Stam's men were cheered on by more than 5,000 travelling fans, but Arsenal were too strong for the Royals who had their chances - through Samuel, Harriott and Kermorgant primarily - but who also needed the excellent goalkeeping of Ali Al Habsi to hold the Gunners at bay.
Manager Jaap Stam named four Academy products in the side to take on Arsene Wenger's men, starting with Dominic Samuel up front, Liam Kelly in midfield and Tennai Watson and Jordan Obita at the back. Five changes in total saw Ali Al Habsi take the captain's armband, Tyler Blackett start in central defence and Callum Harriott named out wide. Arsenal, meanwhile, included Olivier Giroud on the bench and started Alex Oxlade-Chamberlain.
Reading began in composed fashion, but some slick passing from the hosts unpicked the lock to the Reading defence with five minutes gone, Carl Jenkinson collecting a lovely one-two to smash an effort goalwards - but skipper Ali Al Habsi parried it well and the right-back nodded the rebound high over the bar.
Oxlade-Chamberlain then arrowed across the face of goal and just wide of the left post when fed by a perfect pass from Alex Iwobi. Arsenal, at the Emirates, were looking impressive in the final third.
Ainsley Maitland-Niles arced an effort just wide of the right post next, but Reading were holding their own though and Emiliano Martinez made a smart save low to his right to deny Jordan Obita's right footed drive from the edge of the Arsenal box.
Lucas Perez got in behind the Royals back line midway through the half, and through on goal he looked to square it instead of take on Al Habsi, but his ball for Iwobi was cut out by a sliding challenge at the last moment and Reading survived.
McCleary broke at pace but was tackled before he could find a telling pass or pull the trigger on the counter, then at the other end Elneny arrowed an effort into the grateful arms of Al Habsi.
And half a chance presented itself to Dom Samuel on the half hour mark - the striker did well to hold the ball up initially and Evans' low pull back was met by the swinging right boot of Samuel who skewed his effort over the bar.
The Gunners had plenty of goal threat when they got the ball and Maitland-Niles arrowed over next. And the Premier League side took the lead with 33 minutes played - Alex Oxlade-Chamberlain got a yard to shoot and rifled low past Al Habsi and inside the bottom left corner for 1-0.
Reading came within a whisker of equalising two minutes before the break. Harriott cut inside onto his left foot and curled an effort towards goal, it rebounded off the head of Gabriel and looped onto the roof of the net with the wrong-footed Martinez stranded.
From the resulting corner, Samuel miskicked Evans' low ball into the box and Blackett nodded the loose ball towards the goal but it was easily gathered in by the Gunners keeper. And a corner in injury time was half cleared by Arsenal, only for Obita to drill it back into a crowded box and the ball pinballed off two or three bodies and away from goal when it could easily have deflected goalwards.
Half-time: Arsenal 1-0 Reading
A stray Kelly pass gave Arsenal an early chance to break at pace through Perez and he threaded the ball into the path of Oxlade-Chamberlain who burst into the box and shot - but Blackett was back well to get a timely slide tackle in and deflect the ball over the crossbar.
At the other end, McCleary forced an error from the Arsenal defence and scampered away towards goal. Samuel was in space inside him and McCleary tried to find him in the middle, but the ball was intercepted by an Arsenal toe and the move broke down.
Stam introduced Yann Kermorgant soon after and the striker got his head on the end of a good deep Obita cross, but Martinez leapt through the air to save high to his right as it floated back across goal.
Arsene Wenger brought on Olivier Giroud in response and he came close to scoring a second - only for Al Habsi to produce a wonderful one-handed save to claw the striker's header off his goalline. The loose ball was headed back towards goal but Moore nodded it off his goalline to keep the Gunners out against the odds.
Al Habsi was in action again to push an Oxlade-Chamberlain strike away and Iwobi slipped on the ball as he tried to follow it in and put the tie to bed.
Another superb fingertip save from Al Habsi kept the game alive, this time pushing a 22-yard drive from Iwobi over the crossbar. But he could do nothing to prevent Oxlade-Chamberlain making it 2-0 with a powerful drive that deflected cruelly off Obita and into the Reading net.
Reading kept going and Martinez needed to pull off a fine save low to his left to keep a late Kermorgant free kick out, after good work from McCleary and Samuel had earned the set piece. But Arsenal held on to their two goal advantage through to the final whistle and now await their next opponents in the quarter-final.
Full-time: Arsenal 2-0 Reading
Arsenal: Martinez, Jenkinson, Holding, Gabriel, Gibbs (c), Elneny, Maitland-Niles, Oxlade-Chamberlain (Zelalem 80), Reine-Adelaide (Giroud 65), Iwobi, Lucas (Willock 72).
Subs: Macey, Sheaf, Bielik, Bola.
Goals: Oxlade-Chamberlain (33)
Reading: Al-Habsi (c), Watson (Gravenberch 68), Obita, L Moore, Blackett, Kelly, Van den Berg (Quinn 80), Evans, McCleary, Harriott (Kermorgant 57), Samuel.
Subs: S Moore, Wieser, Quinn, Meite, Swift.
Yellow: McCleary, Moore.