In a first-half involving two own goals, the Gas took the initiative just after the tenth minute with Hanlan forcing Sargeant into a save down low. The ‘keeper fumbled the shot into the path of Koiki who stabbed home.

An ugly deflection undid the Gas’ good work ten minutes later as Ling rifled a low cross across the face of goal. Baldwin stretched to block the service, but saw a ricochet take the ball into the goal at the near post.

However, the fortune was repaid moments later with Westbrooke smashing a free-kick against the bar from distance. It rebounded back off the upright before hitting the diving Sam Sargeant and bouncing into the net in an own goal even odder than the first.

The second-half produced less goalmouth action, but plenty of talking points, as a Jamie Turley red card altered the dynamic of the evening. A high boot raised towards young Zain Walker saw the Orient defender sent off, but the Gas’ opposition raised their game at 10 men, solidifying well and disrupting Rovers’ attacking flow for the remainder of the night.

A youthful-looking Rovers side were greeted by fans for the first time this campaign as Leyton Orient welcomed supporters back to the Breyer Group Stadium under COVID guidelines.

Cam Hargreaves, Ali Koiki and Zain Walker were the younger members introduced to the starting line-up, accompanied by experienced heads such as Baldwin, Hare, and Upson sprinkled through the squad.

Ayunga and Little drew attention to the bench too, both returning from injury to feature.

A first half-sight of goal came through Brandon Hanlan on the five-minute mark, with the forward cutting in from the left flank hoping to build on his two goals from the weekend. He struck low with his right, but it lacked his usual venom with Sargeant collecting well.

Brandon Hanlan would be instrumental in the Gas’ next opportunity, with the number 9 standing up his man before darting to his left and wrapping a left-footed effort on goal. Sargeant got to it, low to his right, but fumbled towards the 6-yard area. There Ali Koiki was arriving, following in with predatory instinct and firing home from close-range for his first Rovers goal.

Leyton Orient found their first chance just past the 20th minute, with the home side able to get their foot on the ball and pick passes for the first time in the game. The ball was worked to the right-flank before being fired back into the box searching for Lee Angol in the Rovers area. The attacker connected but flicked his header wide of the target.

Maguire-Drew, who provided that accurate cross, fancied a chance for himself moments later, ghosting by Leahy near the byline on the right, making his way towards goal from the tight angle. He glanced inside to open space for a shot, but Baldwin got himself in the way of the flight of the ball to avert danger.

A looped ball over the top picked out Angol within the next minute, but as the striker saw the net bulge with his one-on-one finish, he looked across to see the linesman’s flag raised.

Ling then made the Orient pressure count, firing in a low cross from the right into a dangerous area. A touch from Baldwin was needed, but it ended up causing more damage than good, as it ricochetted horribly into the net, creeping past Jaakkola at the near post to level things up.

In an incredible balancing of the scales, a cruel deflection then undid Orient moments later. A venomous free-kick from Zain Westbrooke clattered off the crossbar back towards the area, but before any player could react to the deflection, they saw it ricochet off the back of the diving Samuel Sargeant. There was nothing he could do about it as the ball rolled back into the net.

A cracking strike from Westbrooke causing Sargeant’s embarrassment, with an assist from a horrid bit of luck.

Craig Clay, a name familiar with Rovers fans, a scorer in the play-off final penalty shootout against Grimsby, found the next chance for the home side. He pulled down a ball as it rattled around between players outside the box, before taking a touch and firing on the turn with his left. The strike sent Jaakkola stretching but arrowed wide of the goal.

Leahy was well-placed to flick a Lee Angol cross to safety as it whipped across the box just before half-time, with the Gas able to maintain their 2-1 lead at the break.

At half time the Gas swapped goalkeepers, with Jaakkola making way for van Stappershoef.

The first chance of the 2nd half was Orient’s. Ruel Sotiriou jinked his way in off the right side towards the centre of the box posing a big threat to the Rovers goal. He opted to toe a strike with his right foot, but van Stappershoef did well to react, saving with his legs down low.

Ten minutes in, Sotiriou’s side were down to ten men. Youngster Zain Walker reacted well in the centre of the park to get behind the ball. As it bounced up to his stomach, Walker witnessed Orient defender Jamie Turley fly in with a raised boot towards his chest. The young prospect showed great tenacity, undeterred by the nature of the challenge, taking a big hit to his torso. By the time he was up from the tackle, Turley had received his marching orders from the referee and Rovers took the man advantage.

Leahy then picked out Walker in the centre of the area not long later, but the winger headed clear of the bar.

The Gas’ opposition looked to solidify over the next ten or so minutes, stemming Rovers’ attacking flow with men behind the ball.

Josh Hare’s cross would find Brandon Hanlan on the edge of the 6-yard box, but he could only imagine the faintest of flicks, seeing it head through the area and out for a throw-in.

Shortly after, Hanlan would make way for Ayunga, with Liddle coming on for Zain Walker too.

An athletic attempt from Sotiriou needed a stop from JvS not long after, with the bicycle-kick tipped wide by the Dutchman around his left post.

Late on, Ed Upson had a decent chance as Westbrooke slipped him in on the right flank towards the corner of the box. He dragged his shot though, wide past the left post.

Six minutes would be added on by the fourth official with JvS forced into action by a well-placed Maguire-Drew free-kick as it arrowed towards the top right corner in added time. The towering ‘keeper stretched to his left to tip the effort wide and maintain the Gas’ lead. It would be his last call into action, as Rovers held out to progress in the cup.

The Gas return to the Mem this weekend, with League One rivals Plymouth Argyle journeying up to Bristol.

Leyton Orient: Sam Sargeant, Sam Ling, Joe Widdowson (Brophy 46′), Daniel Happe, Craig Clay (c), Jordan Maguire-Drew, James Dayton (Wright 67′), Lee Angol (Johnson 61′), Ruel Sotiriou, Jamie Turley, Hector Kyprianou

Subs: Lawrence Vigouroux, Josh Coulson, Jordan Thomas, James Brophy, Louis Dennis, Danny Johnson.

Rovers: Anssi Jaakkola (Van Stappershoef 46′), Luke Leahy, Alfie Kilgour, Jack Baldwin (c), Josh Hare, Ed Upson, Zain Westbrooke, Ali Koiki, Cam Hargreaves, Zain Walker (Liddle 73′), Brandon Hanlan (Ayunga 73′)

Subs: Jordi van Stappershoef, Mark Little, Cian Harries, Michael Kelly, Ben Liddle, Josh Barrett, Jonah Ayunga.