The towering Norwegian had not scored for over a month but came back with two left foot strikes to sink Killie and take his tally for the season to 10.
Now Rangers hold a nine-point lead over Hibs with just five matches remaining and that should be a large enough advantage to hold off the Edinburgh men and secure the runners-up position.
Dick Advocaat had been complaining pre-match about the lack of goals Rangers had been scoring this season and without picking out Tore Andre Flo for particular criticism, the Ibrox boss let it be known that the Norwegian could have done better.
Either Advocaat had a crystal ball or else Flo took his words to heart because scarcely 40 seconds had past at Rugby Park when the £12m striker fired Rangers into the lead.
It was skipper Barry Ferguson who created the chance with a cute ball from midfield which found Flo on the left side of the Killie box.
There was still some work to be done but Flo went past Chris Innes with some ease before sliding a left foot shot into the right corner, giving Colin Meldrum no chance.
It was the pefect start and Rangers sought to captilise. Flo released Rod Wallace in four minutes with an excellent through ball but the little Londoner pulled his right foot shot wide.
Then in 11 minutes Claudio Reyna’s exquisite pass allowed Billy Dodds the sniff of a chance but he too dragged his effort wide of Meldrum’s right hand post.
The nature of the game changed, however, in 14 minutes when Kilmarnock won a penalty in controversial circumstances. Referee Eric Martindale penalised Arthur Numan for some kind of offence against Chris Innes but the Rangers players were completely bemused by the award.
All of a sudden the responsibility lay with Ally McCoist to haul Killie back into the match and having spoken at length about his desire to net against his old team this could hardly have been a better opportunity.
The former Rangers man struck the kick sweetly enough but Stefan Klos dived to his right to push the ball onto his right hand post and McCoist could scarcely believe his eyes.
The German goalkeeper, who has been outstanding for Rangers this season, had better to come as he pulled off a fantastic blocking save from Andy McLaren’s rebound.
Martindale’s decision inflamed the game, however, and Ferguson was booked for voicing his opinions too vociferously. It also led to a period of concerted Killie pressure, although with no end product.
Gradually, Rangers began to regain the upper hand and just before half-time they increased their lead when Flo claimed his second goal of the match and he celebrated in style in front of the Rangers supporters in the Moffat Stand.
Fernando Ricksen, fresh from an excellent performance at Easter Road, was the creator with a cross from the right which fell nicely at the back post for Flo who clipped a left foot shot into the net.
Killie boss Bobby Williamson immediately changed things at half-time bringning on Christophe Cocard for the luckless Innes, who was also posted missing at the second Rangers goal.
While Killie had some decent moments, Rangers were never really troubled and Klos was scarcely called into action. Indeed once Ferguson regained a grip of midfield there seem little doubt about the outcome.
There was not much happening in attacking sense for Rangers in the second half, although a surging run from Flo in 65 minutes had Killie back-peddaling but his final ball to Billy Dodds was too strong.
Then in 69 minutes Wallace had a great chance to set up Flo for his hat-trick but failed to supply the correct pass, hitting Kevin McGowne as he tried to find Flo at the back post.
It was prove to be a costly mistake because Killie hauled themselves back into the game six minutes later. Rangers were caught out by Freddie Dindeleux’s long ball which found Gary Hay on the left side of the box and he hammered a left foot shot past Klos.
Advocaat made a switch bringing on Kenny Miller for Dodds in 80 minutes and the young striker came desperately close to scoring within 90 seconds of his introduction.
Arthur Numan made a great run down the left and produced the ideal cross. Miller skipped away from Meldrum bu Hay blocked his shot on the line and then the Killie keeper recovered to block Miller’s second effort.
It was enough to take the sting out of any potential Killie recovery and Rangers held on for their win to move ever closer to clinching second spot and qualification to the Champions League.
KILMARNOCK: Meldrum; McGowne, Dindeleux, Innes (Cocard 45); MacPherson, Mahood, Calderon, Reilly, Hay; McLaren, McCoist. Subs not used – Marshall, Mitchell, Di Giacomo, Canero.
Bookings: Ferguson (14), Wilson (25), Porrini (56) Numan (90)
RANGERS: Klos; Wilson, Konterman, Porrini; Ricksen, Reyna, Wallace, Ferguson, Numan; Flo, Dodds (Miller 80). Subs not used – Christiansen, Albertz, Tugay, Fernandes,
Bookings: Calderon (26)
Ref: Eric Martindale.
Man of the match: Stefan Klos
Moment of the match: Klos’s save from McLaren’s rebound after McCoist’s penalty miss.