Defender Stephen O’Donnell’s deflected last-minute winner gave the Hatters victory to send them through to the second round of the Johnstone’s Paint Trophy.
The Scottish right-back shouldered home Ryan Hall’s shot from the edge of the penalty past Orient goalkeeper Charlie Grainger in the 90th minute to prevent the tie from going to a penalty shootout.
It was no more than the Town deserved for an enterprising display against Orient. The Hatters led at the break thanks to a stunning goal from winger Danny Green but the visitors levelled on the hour when Lloyd James converted a penalty after Scott Cuthbert had fouled Scott Kashket.
But just when the game seemed destined to go to penalties after Jack Marriott was sent-off 10 minutes from time, O’Donnell had the last word when he dived to divert a goal-bound shot from Hall in the top corner to send the Town into Saturday’s second round draw.
Showing seven changes to the side that lost to Portsmouth on Saturday, including a first appearance of the season for Luke Guttridge, the Town began on the front foot and on 10 minutes former Orient defender Scott Cuthbert volleyed a dangerous Green corner just wide.
Green was seeing a lot of the ball as the Hatters penned the visitors back, and on 22 minutes the winger tried his luck with a shot from the edge of the box that deflected into the side-netting. From the resultant corner, Green’s dangerous delivery was headed over by Scott Griffiths.
However, Green didn’t have to wait long to break the deadlock when on 29 minutes he fired the Hatters ahead in fine fashion. Receiving the ball on the right-hand edge of the penalty area the midfielder looked up and blasted a blistering shot into the top corner of the net for his first goal for the club.
As the Town’s accurate passing continued to put Orient under pressure, Green came mighty close to doubling his and the Hatters’ tally moments before the break when his volley – after great work from Pelly Ruddock Mpanzu from the left – was cleared off the line by Frazer Shaw.
Mark Tyler kept the Hatters in front with a smart stop following Ollie Palmer’s low shot on the stroke of half-time but the Town came close to going 2-0 ahead four minutes after the restart when Ruddock flashed a shot wide of the target.
Green came close once more on 52 minutes with a firm effort after his initial corner was half-cleared by the Orient defence.
After that near miss the O’s upped it and, after Blair Turgott saw a shot saved by Tyler, the visitors levelled from the spot. Cuthbert tripped Turgott and James rolled home the resultant spot-kick to make it one apiece.
In the incident that led to the Orient equaliser, Cuthbert was replaced by Magnus Okuonghae for his Town debut and the big defender made an immediate impression by booming clear a header with his first touch.
Okuonghae and the Town defence came under pressure as the O’s, buoyed by their leveller, went in search of a second goal. On 67 minutes the Hatters had a fantastic acrobatic clearance from Stephen McNulty to thank for denying the lively Kashket, and a minute Tyler did well to pounce on a low shot from Palmer inside the penalty box.
As time ticked towards the final 10 minutes Marriott headed over when well-placed to meet Guttridge’s left-wing cross, before the young striker was given his marching orders for an off-the-ball incident spotted by the assistant referee.
Despite their numerical disadvantage the Town went in search of a winner and it almost came when Guttridge blasted over following a mazy run from Griffiths.
But, as has been the case in so many of the Hatters’ game this season, particularly at Kenilworth Road, there was a late goal – and this time it favoured the Town. Substitute Hall’s free-kick was blocked by the Orient wall but his follow-up strike flew goalwards, hit the diving O’Donnell on the shoulder and nestled into the top corner.
There was no need for penalties and the Hatters could celebrate a last-gasp victory for themselves.
Town: Tyler; O’Donnell, Griffiths, McNulty, Cuthbert (sub Okuonghae 59); Lee, Smith, Ruddock (sub Hall 72), Green (sub McQuoid 85), Guttridge, Marriott.
Subs not used: Mackail-Smith, Justham.
Attendance: 1,953, including 300 from Orient.