George Moncur scored the only goal of the game as Luton beat fellow Championship side Reading 1-0 in the FA Cup.
The midfielder volleyed the only goal of the third-round tie in the first half to decide the contest at Kenilworth Road.
A much-changed Hatters side had the best of the early chances, Ryan Tunnicliffe volleying James Bree’s cross over, while Elliot Lee also stabbed wide from another right-wing delivery.
Striker Danny Hylton could not reach Dan Potts’ looping header from a corner at the far post and also missed Sam Nombe’s inviting cross from close range, with Moncur’s follow-up effort well blocked.
The decisive breakthrough came on 30 minutes. Bree sent over a high, hanging cross from the right which was brilliantly met on the volley by Moncur, who guided his effort beyond goalkeeper Luke Southwood and into the net.
Reading then upped their attempts to draw level, Sone Aluko narrowly missing the bottom corner after turning his marker inside and out, while debutant Oliver Pendlebury saw his blast parried by Simon Sluga.
Michael Olise could only drag well wide from outside the box for the visitors, before Hylton had a glorious chance to double the Hatters’ lead – but from a yard out failed to beat Southwood from Tunnicliffe’s header.
Luton were indebted to a marvellous sliding intervention from former Royal Gabriel Osho to prevent Sam Baldock from equalising, after Sluga had parried Alfa Semedo’s effort.
Aluko should have levelled on 62 minutes, when left unmarked to meet Tomas Esteve’s cross, but could only lift his effort against the top of the crossbar.
Sluga made an excellent save from Esteves midway through the half, turning his low rasping drive behind, then the Luton goalkeeper collected a close-range header from Baldock.
Sluga then managed to palm Olise’s long-range attempt behind as the visitors began to increase the pressure in search of a leveller.
Tunnicliffe forced Southwood to save at his near post from an angled drive – but with 15 minutes left Sluga made a brilliant double stop to prevent Reading from restoring parity.
First, he blocked Baldock’s 20-yard effort, then got up quickly to prevent Jayden Onen’s follow up with his legs.
Reading should have forced an extra half hour in the final minute of stoppage time, as they went clean through on Sluga, only for substitute Nahum Melvin-Lambert to hit the bar, with Onen putting the rebound over the top.
