After sloppily dropping two points at Dundee last weekend, the onus was on Derek McInnes’ side to respond and they led at the interval thanks to a goal in the 29th minute from returning Venezuela forward Kelsy.

Saints goalkeeper Toby Steward had helped keep the visitors in the game but further efforts from striker Ryan Naderi in the 61st minute and Kelsy again five minutes later clinched a deserved win.

In the 74th minute Saints substitute Kai Fotheringham was shown a straight red card by referee Chris Graham for his high challenge on Gers midfielder Nico Raskin – but only after he was sent by VAR to check his pitchside monitor – before substitute Tochi Chukwuani added a fourth with three minutes remaining.

The Light Blues have won eight and drawn one of their last nine games in all competitions and moved to within one point of leaders Celtic, who travel to bottom side Hibernian on Sunday.

In blustery conditions, Steward should have been picking the ball out of the net in the 14th minute when Badredine Bouanani played a one-two with Kim Min-su and burst through the St Johnstone defence but failed to hit the target from eight yards.

Moments later, Steward pushed a decent drive from Kelsy, back in the side at Djeidi Gassama’s expense, around the post for another fruitless corner before the McDiarmid Park keeper thwarted Kim from close range.

In the 25th minute, amid swirling wind and rain, Bouanani’s explosive drive from inside the box was blocked behind for another cleared corner.

However, the home side forged ahead moments later, after Kim’s pass sent Naderi racing down the left flank. The big striker may have taken on a shot himself but he squared to Kelsy for an easy tap-in, easing building anxiety inside the stadium.

Two minutes later, Kim fired a low drive against the post from the edge of the box but in the 34th minute St Johnstone striker Josh Fowler escaped the Gers defence to take a Jamie Gullan pass before curling his effort wide.

Three minutes later, after St Johnstone’s Cheick Diabate gave the ball away, Kelsy was perfectly set up by Naderi – who again himself could have shot – but Steward brilliantly saved.

Fotheringham, Danny Schmidt and Bozo Mikulic came on for Saints at the start of the second half, with Fowler, Josh Campbell and Daniel Finlayson departing.

The visitors went flat out to get level and Gers keeper Ivor Pandur tipped a powerful drive from Enes Alic over the bar.

Steward parried an angled drive from Kim and Naderi forced the ball over the line, before Kelsy tapped in from close range following a corner which made its way to the back post.

Fotheringham was dismissed and Rangers pushed with more ease to increase their lead and Chukwuani had the easiest of tasks to make it four when he knocked in a cutback from fellow substitute Gassama.