At this stage of the campaign it’s all about getting results and with two more tricky away fixtures against Hamilton and Aberdeen coming up the Light Blues showed great determination to get a victory they so desperately needed.
Lafferty returned to Gers’ starting line-up for kick off as Smith made just one change to his team.
The Ulsterman missed the weekend’s action because of a knee injury which flared up while he was on international duty with Northern Ireland last month.
But after being passed fit by the manager following yesterday’s training session at Murray Park the towering striker went straight into the first XI in Perth and put in a great shift.
Rangers have bounced back with a victory in their next league game after each of their five SPL defeats so far this term.
But on this occasion they had to overcome a tricky playing surface and a blustery wind which picked up after half time.
Saints were positive from referee Crawford Allan’s first whistle with forwards Danny Invincibile and Jordan Robertson using their physical strength to test Steven Whittaker and Gers skipper Davie Weir.
But with ten minutes on the stadium’s digital clock neither Allan McGregor or Peter Enckelman had been tested and this provided a bit of hope for the home support as they urged their players forward.
Using a 4-4-2 formation against the Champions was a bold move by Derek McInnes but on 19 minutes he would have been gutted at his side’s defending as the Light Blues took the lead.
A poor header from Danny Grainger to Enckelman gifted the ball to Lafferty.
The striker calmly rounded the Finn and showed his quality to roll the ball in to the empty net in front of the travelling Bears who did not let the 6pm kick off stop them from supporting their side.
The goal helped to ignite this fixture and after a confident start St Johnstone’s backline started to look nervous with the Ibrox men pushing up the park in search of a second.
On 31 minutes a raking 50 yard pass from Sasa Papac flew over the head of Dave Mackay but the Saints skipper did well to get back and deflect Lafferty’s first time effort out for a corner.
Gregg Wylde took the resulting set piece and Duberry had to stoop to head clear as the ball dipped dangerously in to the six yard box.
The Saints anxiety soon turned to frustration and former Chelsea defender Duberry and left back Grainger could be seen exchanging a few verbals in the centre circle.
The home side responded by getting men forward and a deflected effort from playmaker Murray Davidson was watched closely by the diving McGregor who could not stop the ball going out for a corner.
On 39 minutes Crawford Allan flashed his first yellow card of the game to Lafferty for dissent.
The ref wrongly awarded a free-kick in Saints’ favour after Laff and Grainger tussled for the ball on the right flank.
Kyle wriggled his way clear in to a crossing position but a foul was given and he punched the ball in frustration as it lay on the turf.
The first-half finished with Rangers on top and it was a deserved lead.
But with just a single goal separating the teams at the interval McInnes’ men were not out of this contest yet and in the second period they always looked a threat.
Rangers, however, maintained control at the restart with Steven Davis again pulling the strings in the engine room.
And on 48 minutes a ten yard burst from jet heeled Wylde won a corner and again his accurate delivery caused havoc with the wind now swirling around the ground.
The game was now going from end to end and on 55 minutes the travelling support had their hearts in the mouths as a low, inswinging cross from Kevin Moon almost caught out McGregor who swiped the ball away from his far post.
McInnes quickly made a double substitution with his side in the ascendency with Peter McDonald and Lithuanian Arvydas Novikovas going on.
And within minutes Saints were denied by another fine save from McGregor.
Poor defending from a flighted cross by Wylde saw the ball arrive at the feet of Davidson and his shot across goal was brilliantly palmed away by the Scotland keeper before Weir made another despairing stop.
Smith joined Ally McCoist and Kenny McDowall in the technical area with his players pegged back and it was not long before youngsters Jamie Ness and John Fleck were introduced for Lafferty and Wylde.
Initially this did little to stop St Johnstone’s pressure and McGregor again had to be sharp to hold a glancing header from Jordan Robertson from Peter MacDonald’s cross.
But with seven minutes left the three points were in the bag and it was no surprise that the industrious Naismith was the player on target.
He tried a one-two with Jelavic on the edge of the 18-yard box but having continued his run he got the break of the ball and unleashed a terrific low shot which bulleted past Enckelman who dived helplessly to his left.
Jelavic could have bagged a third when he skipped past two challenges before smashing the ball off the underside of the bar.
But the second goal was just what the doctor ordered for Rangers who avoided a nervy end to this game to move to the top of the SPL, albeit for just 24 hours.