Former Celtic striker Hyeon-Gyu Oh returned to Glasgow to haunt 10-man Rangers as he scored the only goal in Genk’s incident-packed 1-0 Europa League win at Ibrox.

The South Korea international had a first-half penalty saved, hit the winner after 55 minutes and later had a tap-in chalked off after he strayed offside.

Rangers – who had Mohamed Diomande sent off after 41 minutes – did not muster a shot on target after the 34th minute and were booed off when the final whistle was blown.

The result increases the pressure on Russell Martin, whose side have won four of their first 14 games in all competitions this term.

Genk were the ones asking questions for much of the first half at Ibrox, with Zakaria El Ouahdi proving a thorn in Jayden Meghoma’s side on the right. Oh flashed his connection on a dangerous ball in from the right-back over the bar from six yards; Patrik Hrosovky hit the post from a similar distance shortly afterwards.

That said, Rangers might have been ahead had it not been for an incredible goal-line clearance from Genk captain to hook John Souttar’s goalbound header away.

Rangers then appealed for a penalty when a James Tavernier header struck the outstretched arm of Joris Kayembe, but after he was sent to the VAR screen, referee Matej Jug upheld his decision of no penalty, owing to an apparent push from Tavernier on Kayembe.

Within three minutes, the hosts were reduced to 10 men. Diomande’s tackle caught El Ouahdi above the ankle and he was shown a straight red card. He lingered by the tunnel, hoping for VAR intervention, but it did not come.

To round off the first-half drama, Genk were awarded a penalty after a second VAR review, with Tavernier having clipped Yaimar Medina as he cut into the box from the left. Oh avoided Butland’s gaze as he prepared to take the spot-kick, but the former England goalkeeper made a strong save to deny him.

But Oh finally scored the goal he had been hoping for early in the second half. Jarne Steuckers’ brilliant ball found him completely unmarked and he was able to finish clinically under little pressure.

He tapped in a second with 20 minutes to play, which was quickly ruled out, but in the end, just one was enough.

Martin: Red card changed the game – but we’ll grow after tonight

Rangers head coach Russell Martin speaking in his post-match press conference:

On his future:

“I don’t think a game where we’re down to 10 men for that long changes things a huge amount.

“I feel nothing but support.”

And speaking to TNT Sports:

On the performance:

“I think it was difficult as we were down to 10 men for so long. We had good control in the first bit of the game, then had a tough spell where we had to defend a little bit as we weren’t good enough or clean enough with the ball. We rode that out, then Dio gets sent off and that changes the game.

“I thought the lads were good second half. We actually looked a threat on the break, they wanted to take the ball, they stuck together. We wanted to be aggressive with it to try and cause them problems as well, then they score a goal we shouldn’t concede. We have them in the corner, should probably foul or at least take the ball and then, a couple of bad decisions later, it’s a goal.

“But they stuck at it. I’m proud of that second half. Playing with 10 men for so long against a decent team is not easy, so it is what it is.

On how far Rangers are from things clicking:

“Not far – and I think we’ll learn and grow from tonight. I think they did well with 10 men for a long time to play.

“As much as it was good evidence for us last Saturday, about the good feeling they had after the game, there will be stuff tonight and tomorrow that is really clear for the players, so there will be a lot of learning from tonight.”

On Rangers fans’ frustration:

“I’ve said so many times before, the only thing that will impact that is winning football matches.

“Inside the building, they’ve been amazing. The process, the players the staff, so we just have to keep focusing on that, then the outcome will end up being positive and hopefully that will end up turning the supporters and their feelings.”

Boyd: Rangers have no option but to start new manager search

Former Rangers striker Kris Boyd on Sky Sports News:

“Andrew Cavenagh, the Rangers chairman, was at Ibrox tonight, and with the chorus of boos at the end from the fans that were still there, he will now understand what’s been going on now for a number of weeks.

“He has experienced Rangers playing in Europe and seen and heard what European nights can be at Ibrox and on the road, but tonight he’s got to be sitting asking himself if this is what he wants as a Rangers chairman because it seems there’s a whole disconnect from the club.

“The fans have totally finished, they feel as if it’s time up anyway.

“I think Patrick Stewart [Rangers CEO] will have a lot of questions to answer now as well. The Rangers fans already turned on him with the protests at the weekend and now Rangers are going into a period where the next three games are away from home and it’s not going to get any easier.

“A lot of Rangers fans were expecting it [Russell Martin’s sacking] to be after the Hearts game because of the negativity that was there.

“Rangers backed their manager and, because it’s the start of a new project you don’t want to seem to be giving up straight away, but looking at it right now there is no other option than to start looking for not only a new manager, but I think the recruitment needs an overhaul at Rangers.

“Once again, I can’t sit here and criticise the recruitment teams that have been there in the past and then look at this one and let them get away with it because the amount of players that have came through the door.

“Youssef Chermiti was given an opportunity this evening as well. I know Rangers go down to 10 men and it becomes difficult for him in the second half, but I’ve never seen anything in the first half that’s going to excite me. When you’re signing that type of player, they have to come in, they have to make a difference and it’s not happening for Rangers.

“He’s the one that’s the big transfer fee, he’s going to carry that but there’s others in that Rangers team that just look absolute miles off where they need to be if they’re going to be successful

“Ultimately the Rangers manager Russell Martin will be te one that ends up paying the price for it but, for me, there’s other people at the football club that need to be held accountable as well because right now the disconnect from the stands onto the pitch and beyond is as bad as I’ve ever seen.”

Souttar: Players frustrated, just like the fans

Rangers’ John Souttar speaking to TNT Sports:

“Frustrating night. I thought we started the game pretty well, had a few chances. The sending off makes it difficult. Second half, we tried to play high, tried to get a few chances and we had a few, but it’s frustrating.

“If I knew what was going wrong, I’d try my best to help it. It’s numerous things. It’s difficult to analyse it right after the game, so it’s difficult for me to answer that.

“When we get a goal early on here, it lifts the whole crowd. And if we don’t get that, it’s difficult.

“I understand the frustrations; it’s the exact same in there. It’s not like we’re on different pages. We can only turn it around by performances and winning games. We need to do that quickly.”