ALEX Rae believes Rangers will have to nullify the threat posed by the form striker in Scotland if they want to beat Aberdeen at Pittodrie on Wednesday night and keep alive their hopes of pipping Celtic to the Ladbrokes Premiership.

Derek McInnes’s men have successfully overcome their patchy early-season form in the past few months and moved up to fourth place in the top flight table thanks in no small part to Sam Cosgrove’s goals.

The 22-year-old Englishman had scored just once in his entire career before October despite spending four seasons as a professional playing for Wigan Athletic, Barrow, Chorley, North Ferriby United and Carlisle as well as Aberdeen.

However, since bagging a double in a 4-1 win over St Mirren at home the 6ft 2in forward hasn’t looked back and has netted no fewer than 10 times in 15 games.

He is sure to have a point to prove in midweek as he was controversially ordered off against Rangers at Ibrox at the start of December in a match his team won 1-0 thanks to a first-half Scott McKenna effort.

Rae, the former Rangers midfielder turned Radio Clyde pundit, has been impressed by Aberdeen’s resurgence and Cosgrove’s form up front and feels Steven Gerrard’s charges will need to be at their best to end a four game winless run against their fierce rivals and maintain the pressure on the league leaders and defending champions.

“Derek McInnes has managed to have continuity even though he loses key players every summer,” he said. “Derek has guys in his team who have been consistent – Andrew Considine and Graeme Shinnie. They also have one of the best centre backs in Scotland just now in Scott McKenna. They are quite strong through the heart of their team.

“But big Sam Cosgrove has been a revelation. Eight weeks ago you would have said: ‘They’ll be looking to replace him in January’. But he has been one of the most prolific strikers in the country in the past two months. Rangers will have to cope with his physical threat to win on Wednesday. He is very dangerous in the air.”

Rae added: “Rangers’ results against Aberdeen this season haven’t been good enough (they have lost two and drawn one of their three encounters). If I was in the Rangers dressing room I would be looking to overturn that.

“Pittodrie isn’t an easy place to go. If the weather stays the same it is going to be freezing and they are going to have to deal with the elements way up there on the North Sea.

“For Rangers, it is about rolling up their sleeves and going about it the same way they went about the Celtic game last month and the Livingston game last weekend. It is about that kind of tempo and mindset. Steven Gerrard says quite often ‘you have to earn the right to play’. There are no truer words when you go to Aberdeen.

"It is a must-win game because of the Kilmarnock result (Rangers lost 2-1 at Rugby Park last month). As much as Celtic have been outstanding on the road, the same hasn’t been true on the road. Rangers need to keep applying pressure and hope at some point they slip up.

“I appreciate Celtic have the biggest squad of players in the country, but they are without some key men. Dedryck Boyata, Filip Benkovic and Kieran Tierney are all out. That is three out of their back four, guys who would be automatic starters. If Rangers win these sort of games against Aberdeen it will keep the pressure on them.”