Glasgow: Rangers manager Ally McCoist believes Inverness Caledonian Thistle pose his side their greatest test of the season so far.

The Third Division leaders welcome Terry Butcher’s Scottish Premier League side to Ibrox for their League Cup quarter-final on Wednesday.

The Gers are looking to claim their second top-flight scalp of the season against Inverness after knocking out Motherwell in the previous round.

But Ibrox boss Ally McCoist reckons beating Caley Thistle will be even tougher.

Motherwell arrived at Ibrox last month as Scottish Premier League leaders while Rangers were struggling to adjust to life in the Third Division.

However, McCoist’s side made a mockery of their bottom tier status with a dominant display in a 2-0 win.

But the Rangers boss expects Inverness to have learned a valuable lesson from seeing their fellow top-flight side come unstuck.

“We can do it again and beat an SPL team, absolutely. But it will be just as hard if not harder,” McCoist said.

“Inverness will have watched the Motherwell game and that night was the best so far for our new team.

“It was like a European night with the incredible support we had and it was arguably our best performance so far.

“But the Inverness boys will know what to expect now. Although Stuart McCall and Kenny Black would have done their jobs, I think the Motherwell boys, perhaps even subconsciously, maybe didn’t know what to expect.

“Inverness will know what they are up against.”

Rangers will be on a high having picked up their first away win of the season against Clyde on Sunday but will have their work cut out for them against an Inverness side who are unbeaten in seven matches and have netted 12 times in their past four games.

Old Firm rivals Celtic are also in League Cup action as they take on St Johnstone at Parkhead on Tuesday.

The Hoops suffered a shock 2-0 defeat to Kilmarnock on Saturday just days after earning plaudits for their battling performance in a last-gasp defeat to Barcelona in the Champions League.

Neil Lennon’s side have already tasted defeat to St Johnstone this season having lost at McDiarmid Park in a league fixture

And Lennon is demanding an immediate improvement from his side when they take on Steve Lomas’ side on Tuesday.

“I am very disappointed; it’s as poor as we’ve played in my tenureship here and I’ll be looking for an instant reaction on Tuesday,” the Celtic manager said.

“There will be changes. I can’t accept that. It was like we were out for a testimonial in the first half. We weren’t turning them or stretching them.

“There were times we were passing for the sake of passing and I want better. I want players to push each other on but I didn’t see enough of that.”

In Tuesday’s other quarter-final, high-flying Aberdeen take on St Mirren at Pittodrie.

The Dons, who sit in third, are unbeaten in 12 matches since they lost to Celtic on the opening day of the season.

They will be looking to Niall McGinn to fire them to the semi-finals after the Northern Ireland striker scored for the fifth consecutive match in Saturday’s defeat of Dundee.

In Wednesday’s other tie, Dundee United take on Hearts at Tannadice.

Peter Houston’s side ended a run of six matches without a win when they defeated St Mirren on Saturday while Hearts had to fight to claim a last minute equaliser in their 2-2 draw with Ross County.

United will have former Hearts favourite Rudi Skacel available for the match after making his debut for his new side at the weekend.