Miles Storey ensured Caley Thistle breathed a sigh of relief on a day their cup dreams could have been washed away.
His second-half winner put Caley Jags into the final of the Challenge Cup – against Raith Rovers on March 28 – for the fifth time, in horrendous conditions that could have seen the game stopped.
Fellow scorer James Keatings was unjustly sent off – given a second yellow for diving, despite clear contact on him before he went down.
Keatings had dragged Inverness level just before half-time after an early Dapo Mebude goal had them trailing.
But with legs heavy and the pitch heavier, Inverness mustered enough resolve to book their place against Raith Rovers at the end of next month.
Caley Thistle assistant boss Scott Kellacher said: “Both teams did great considering the conditions. The pitch held up very well.
“We scored from a set-play, which we are quite good at, and it gave us something to hold on to.
“We had to sit on it for the last 10-15 minutes when Rangers had a lot of the ball. I thought we managed the game well in the later stages.”
Mebude, a talent highly thought of within the Rangers ranks, punished the early anxiety.
With the ball coming back to him off Kevin McHattie, Mebude angled his shot well across Mark Ridgers and into the bottom corner.
It served to startle the Caley Jags, coming up against the first colts side to make it to this stage of the competition. Their passing from the back was shaky, clearances rushed and thoughtless.
Graeme Murty’s youngsters are a permanent counter-attacking threat, with Mebude and Jake Hastie able to drift wide and the tricky, slaloming Kai Kennedy carrying the ball through the quagmire with relative ease. Inverness tried to go wide and deliver balls into Jordan White. Shaun Rooney set off on numerous gallivanting runs down the right but was hemmed into corners before finding an escape.
The young Rangers side showed the assurance of a team used to making it to this stage of tournaments.
Had Mebude shown greater composure when Kennedy picked him out at the back post, the game could have been further out of the reach of Inverness.
The crossbar came to the Highlanders’ rescue – as did Hastie’s miscue with the winger poised to tuck away the rebound.
It took the hosts until a minute before half-time to get back into the game. Storey, with his first meaningful contribution of the game, stood a cross up to the back post for White, with his header reaching Keatings on the edge of the box.
Keatings’ shot took a deflection off Rhys Breen on its way into the bottom corner but it came as welcome relief to Inverness, who had struggle to impose themselves on the game. Keatings’ Caley Thistle career has been stop-start, at best, with injuries interrupting some promising performances.
But Greg Aitken’s decision to send him off for diving – his second booking – will have left him questioning whether he wronged someone in a previous life.
His run across Ciaran Dickson was clever and the midfielder clearly checked him.
His fall may have looked dramatic but the replays clearly showed Dickson impeding Keatings as he surged towards the box.
It was hard not to feel sorry for him as he trudged off.
There was further dubiety when Caley Thistle thought they had the lead. A hopeful punt from Ridgers evaded everyone in the Rangers defence bar Tom Walsh, who was unchecked as he lifted the ball past Andy Firth. Belatedly, however, the linesman’s flag came up.
Their persistence paid off in 73 minutes.
When Firth parried James Vincent’s effort at the back post, Storey was lurking near the penalty spot. With a swift strike, the ball was despatched back past Firth into the net.
“I was very impressed with Rangers,” added Kellacher. “They took the game to us straight away.
“We told our boys it wasn’t going to be easy. They had to roll their sleeves up and get on with it and they did.”