The former Rangers captain believes Kelsy, who impressed in recent games, was missed in the Dundee draw.

Kelsy was brought on after 75 minutes in the draw at Dens Park, with Ryan Naderi left to lead the line alone.

Ferguson said: "I liked the way Kelsy and Naderi were working.

"I thought the formation was looking good and, most importantly, they were winning games of football."

He believes Naderi plays better with a partner and was isolated at Dens Park.

Ferguson added: "Derek made the decision to change Kelsy with Bouanani, and he did come up trumps with his goal and he looked at a real danger, but I just like the two big boys up top, I think it’s worked really well for Rangers."

The former skipper is also not too worried about Rangers being four points behind in the title race.

He sees it as a minor gap given the long season ahead.

Ferguson said: "The reason I’m not getting uptight is because there’s a hell of a lot of football still to be played.

"I think there will be points dropped over the season by both Rangers and Celtic.

"I look at that block of eight games for Rangers, seven wins and one draw. It’s not a bad run.

"I’ve liked what I’ve seen in the last eight games. I think Rangers have got an edge to them which I thought was missing previously."