Luton crashed out of the Carabao Cup as they were beaten 1-0 by League One Exeter at St James Park.
Demetri Mitchell scored the only goal of an absorbing game with seven minutes remaining before he was later sent off after picking up a second yellow card.
Luton made 10 changes to the team that picked up their first point of the Premier League season with a 1-1 draw against Wolves at the weekend, while Exeter made five to the side beaten 3-0 at Oxford.
The Hatters started brightly as Tahith Chong broke into the box, only to be denied a shooting chance by a superb tackle from Alex Hartridge, before Luke Berry’s long-range effort was tipped over the bar by Exeter goalkeeper Vili Sinisalo.
Cauley Woodrow then struck the outside of a post after Exeter fell asleep at a quick throw-in before a rare Exeter attack ended with James Scott curling narrowly wide from 25 yards.
Mitchell’s inviting cross was narrowly in front of Scott as Exeter started to come into the game before the former Manchester United youngster saw his shot to the near post saved by Tim Krul.
Elijah Adebayo headed wide for Luton as the game approached the half-hour mark before he saw a shot from 10 yards saved by Sinisalo before a lovely Exeter move ended with Caleb Watts firing high from 25 yards.
Exeter had a great chance to break the deadlock after 61 minutes when Mitchell robbed Joe Johnson and sprinted goalward.
His shot was saved at the near post by Krul before Kyle Taylor fired the rebound wide from 15 yards.
Both teams then made changes – Luton with four in one go – before Adebayo headed wide and substitute Jacob Brown headed straight at Sinisalo from point-blank range.
Luton were getting back on top, with Carlton Morris seeing a header cleared off the line and Brown glancing another header wide before Exeter went in front in the 83rd minute.
Substitute Yanic Wildschut did well down the right and his deep cross was not dealt with, allowing Mitchell to nip in and poke the ball in off the underside of the bar from close range.
Wildschut then fired tamely at Krul before Mitchell then received a second yellow card for a foul with two minutes remaining.
It was now all hands to the pump for Exeter, who defended as though their lives depended on it as a raucous sell-out crowd cheered them on.
And, as much as Luton huffed and puffed, they could not breach an outstanding Grecians defence as Exeter beat top-flight opposition for the first time since 1981 and reached round four for the first time since 1989.
