Shota struck his fourth goal in three appearances for Rangers while Tore Andre Flo converted McCann’s pass to claim his 12th of the campaign to see off Saints, who proved to be fierce competitors.
The torrential rain which had fallen on Perth produced a saturated surface which made it difficult for Rangers to play their passing game although Advocaat’s attacking formation certainly tried to make the best of the conditions.
With Ronald de Boer on the right and Shot Arveladze on the left of Flo up front, the Rangers boss clearly showed he meant business but a combination of the weather and the fighting spirit of Saints meant the game plan did not quite work in the early stages.
Indeed the Perth men had the better chances at this stage. Veteran striker Willie Falconer had two very good chances inside the first 22 minutes but fortunately for Rangers he missed them both.
The former Celtic and Aberdeen striker had more time than he thought to connect with Paul Hartley’s cutback in 16 minutes after the Saints’ midfielder had cleverly skipped away from Lorenzo Amoruso but he hit his shot wildly high and wide.
Then in 22 minutes, when Rangers failed to clear their lines properly despite three attempts, Falconer was presented with a clear header from the same provider but again missed the target from only 12 yards.
Bert Konterman also had to take the penalty a booking for pulling back Paddy Connolly in 15 minutes when he clearly felt the Saints striker was going to cause a problem.
Rangers, missing Craig Moore following his neck injury against Moscow Dynamo on Thursday night, had some decent moments of their own but not for the first time this season they had no end product.
Saints forced them into long range efforts most of the time and in essence there was very little for keeper Alan Miller to worry about which was obviously a considerable concern to Advocaat.
Claudio Reyna had two decent efforts. In nine minutes his right foot drive was deflected for a corner and then in 38 minutes he came close to chipping Miller from 25 yards after a lovely lay-off from de Boer following Ferguson’s clever pass but the ball dropped just over the bar.
Fernando Ricksen found some room on the right but invariably wasted the freedom with a poor cross. And when he found himself in decent space in 25 minutes following Flo’s chest down, his right foot shot was deflected off Darren Dods for a corner.
The surface water on the pitch was clearly having an effect, the best evidence of this coming in 42 minutes when de Boer fell on his backside splashing rainwater into the air as he tried to connect with Ferguson’s pass.
It also lead to bookings for Saints’ Stewart Mcluskey in 41 minutes and Flo in 43 minutes when their momentum on the wet surface resulted in fouls on Arthur Numan and Nick Dasovic respectively.
Regardless of the conditions, Advocaat clearly had some harsh words to say to his players at half-time and it is not the first time he has done that here. This time last season he had a real go at his players when they lost in Perth.
He also made a switch, bringing on Neil McCann to play on the left side of midfield pushing Numan into a central role and bringing off Reyna.
Within three minutes his side had the lead and it was Arveladze who grabbed the goal – his fourth in three games for the Light Blues.
It was Michael Ball who instigated the chance when his ferocious 30-yard drive was deflected onto the crossbar by Grant Murray as keeper Alan Miller pawed thin air.
Arveladze was the quickest to react and dived headlong to head the ball into the unguarded net and immediately put Rangers much more at ease.
In fairness to Miller – the Englishman on loan from Blackburn – he made a crucial save from Flo in 55 minutes which kept Saints in the game as a second goal at this stage would surely have floored the Perth side.
McCann set up the opportunity when he cut in from the left and looked to play in Arveladze in a central position. Cleverly, the Georgian striker left the ball for Flo who cut onto his left foot and hammered a low drive which Miller brilliantly blocked with his right hand.
Flo, however, was not to be denied and he succeeded in making the game safe in 69 minutes with his 12th strike of the season, finishing off what was a quite excellent Rangers move.
It was skipper Ferguson who set it all up with a crisp pass into McCann who had found some space just outside the box. With efficiency and precision he found Flo in the centre and the towering Norwegian controlled the pass well before side-footing a right foot shot into the left corner.
Flo might have scored again two minutes later when de Boer cut the ball back to him on the right side of the box but Miller pulled off a fine save.
Ball was booked for a foul on Keigan Parker in 75 minutes and then McCann was cautioned for bringing down Hartley, who stupidly earned himself a caution for squaring up to the Rangers winger.
It was all a bit unnecessary as Rangers had the game wrapped up. Saints kept battling but other than a Paddy Connolly header in 66 minutes which Klos held they rarely troubled the Ibrox men.
Both Mo Ross and Claudio Caniggia got a taste of the action in the final moments and while this was far from a classic, the job was done and Rangers left with the three points they came for.
ST JOHNSTONE: Miller; Murray, McCluskey, Dodds, Lovenkrands; Parker, Dasovic, McBride (Fotheringham 84), Hartley; Connolly, Falconer (MacDonald 73). Subs not used – Cuthbert, Russell, McClune.
Bookings: McCluskey (41), Hartley (76)
RANGERS: Klos; Amoruso, Konterman, Ball; Ricksen, Reyna (McCann 45), Ferguson (Ross 82), Numan; de Boer, Flo (Caniggia 85), Arveladze. Subs not used – Christiansen, McHale.
Bookings: Konterman (15), Flo (43), Ball (75), McCann (76)
Ref: Stuart Dougal.
Att: 8,351.
Man of the match: Shota Arveladze
Moment of the match: Reyna’s attempted chip of Miller in the first half.