Rangers reduced the gap at the top of the Scottish Premiership to 15 points as bottom side St Johnstone succumbed to another defeat that leaves them further adrift at the foot of the Scottish Premiership.

Rangers chief executive Patrick Stewart said before this fixture the board were backing manager Philippe Clement despite a wretched run of away results, on the assumption that would improve.

Some supporters groups, angered with the way the club is being run, had called for a walkout protest in the 55th minute and a minority of fans followed through with it, to the fury of many inside Ibrox as boos rang out.

What was required on the pitch was a convincing performance. Rangers got that, for the most part, but Simo Valakari's side helped them with some eye-wateringly poor defending in the opening stages.

The Ibrox side had dropped points in their previous two away fixtures but the generosity of the visitors and some crisp finishing aided their cause here.

Inside 25 minutes, Rangers were three up and the game was over.

Hamza Igamane, Vaclav Cerny and Mohamed Diomande all capitalised on poor defending as Clement's men looked intent on blowing their opponents away.

An early goal was sought to ease tension and came from a common source. St Johnstone switched off at a throw-in, Cerny fed Diomande who cut back for Igamane and he made no mistake with his 12th goal of the campaign.

It was poor from Valakari's side and again so when Robin Propper won possession and Cerny scampered clear to finish past debutant Andy Fisher in goal.

A third came as St Johnstone looked likely to implode. Jack Sanders aimlessly headed straight to Diomande and he nodded the gift home.

At that stage it seemed a case of how many. To their credit, St Johnstone grew after changes at the break.

From their first effort on target, they scored. Max Kucheriavyi floated a delightful corner in and Sanders atoned for his earlier error by netting a consolation.

That sparked a little more threat and nervousness around Ibrox but was ultimately too little too late.

Substitute Oscar Cortes came closest to extending Rangers' lead with a curling shot that Fisher superbly diverted.

Wins are all that matter for Rangers now. Further slip-ups are unlikely to be accepted by the frustrated fanbase and this fixture was in many respects the perfect one given St Johnstone's own struggles.

It proved exactly that. There was a lot of pressure on the Ibrox players and their manager given their calamitous away form.

At home, Rangers have been strong and that continued here.

They could and perhaps should have made it far more comfortable, though, given the chances they had, and will be a little frustrated not to have surged out of sight.

The outcome lifts a little of the gloom, but what the Ibrox side need is a sustained run of victories to see if they can eat into Celtic's lead.

That may buy a little time while an independent review of operations is conducted. That said, it is clear some fans will take plenty of convincing the club are on the right track.

Valakari has a determination to play football from the back. Early on at Ibrox, that looked very risky but they stuck with it.

The concession of the opener was cheap. The second and third were also far too easy.

The Perth side are capable of producing some good moments going forward, but look so vulnerable to conceding it's little wonder they are toiling at the foot of the Premiership, with the deficit now nine points.

The question seems to be whether the manager has the personnel to play the way he wants. They were cut open far too easily for the goals and the game was pretty much done before the half-hour mark.

Saints were ruthlessly punished but fully contributed to their own demise.

There was a clear improvement after the break as they looked more solid and got a consolation goal, but it does nothing to change the challenge they face in the remainder of the season.

Rangers manager Philippe Clement: "I wanted more in the second half than we gave. There is a lot of potential to make things better. We lost some fluidity in our attacking part.

"In the first half there were a lot of good actions, good goals. There are a lot of positives in the group getting better and better, it's getting consistency in the away games.

"It's always about the next game. I will guide them towards the next game to win against Aberdeen - never a guarantee."

St Johnstone manager Simo Valakari: "It's only us we can blame. We are making too many mistakes, we all know it. We just need to be better in those moments.

"I know my players, they have this spirit, they have this capability to play good football. If you make those [bad] decisions, you get punished. It's not about taking risks."