Rangers' Steven Gerrard "can't wait for the whistle to go" against Celtic on Saturday after his Scottish Premiership leaders gained revenge over St Mirren.

The Buddies knocked Gerrard's side out of the League Cup two weeks ago.

But first-half strikes from Kemar Roofe and Alfredo Morelos were enough to send Rangers into Saturday's Old Firm derby 16 points ahead of the title holders.

Gerrard said Morelos' scoring return to the starting line-up gives him "some big decisions to make" for Saturday.

"It was another strong performance from Glen Kamara and from Joe Aribo, while Ianis Hagi has contributed again with an assist, but I pick a team I think can do a job against Celtic, not really on who scored in the last game or who is on form," he said. "In terms of how it looked on the eye, in terms of style, it was very patchy, but we're in a good place."

Indeed, in ending Saints' run of seven games unbeaten at home, Rangers have won four in a row since that shock cup exit and extended their run of league victories to 13 in what is their best top-flight start since 1928.

Considering that League Cup result, and the fact seventh-placed St Mirren had made their best league start since 1988, this was always going to be a big test for Rangers' title credentials.

It was no surprise home manager Jim Goodwin returned to the more defensive starting line-up that secured their place in the semi-finals and Jamie McGrath, scorer of two of their goals that night, was first to threaten as the midfielder dispossessed a lazy Steven Davis and fired a low drive straight at goalkeeper Allan McGregor.

St Mirren were looking as full of confidence as Rangers were with trepidation as two of the three players returning to the home line-up combined to give the visitors another scare.

McGregor, making his 400th appearance during two spells with the Ibrox club, was unable to hold Dylan Connolly's low shot through a sea of legs and Jonathan Obika could only scoop his close-range shot on the turn over the crossbar.

But St Mirren's early work was undone when Hagi pounced on a mix-up between two opponents and played through for Roofe to fire past goalkeeper Jak Alnwick via a deflection off the hosts' other League Cup scorer, Conor McCarthy.

The striker's 10th goal in 14 games was quickly followed by Morelos' first in nine as the Colombia international pounced on Joe Shaughnessy's messy backpass to slot past former Rangers goalkeeper Alnwick.

St Mirren again started the better after the break, but it was Rangers who came closest to adding to the scoreline as Alnwick saved from Morelos and the visitors appeared able to coast the rest of the game as they preserved energy for that even bigger test to come.

Man of the match - Jonathan Obika

What did we learn?
Lightning did not strike twice for St Mirren - it rarely does for provincial sides against either half of the Old Firm - but they can take heart from troubling the league leaders once again.

Goodwin got his tactics spot on and will hope this is a mere blip in a fine run since ending a run of six straight defeats in October around the time of their Covid outbreak.

Rangers, meanwhile, continue to grind out the results despite in recent weeks failing to replicate their early season fluency but will need to combine those elements of teamwork and tenacity to overcome a Celtic side recovering from their own sticky patch.

It was also a win achieved while dropping winger Ryan Kent to the bench and that, along with Morelos' goal on being restored to the starting line-up, leaves Gerrard with some big decisions to make on Saturday.

What they said
St Mirren manager Jim Goodwin: "We always knew how difficult a task it was going to be and I don't think we did enough to win the game, but I thought we controlled long periods of the game without really troubling Rangers. We gave away a couple of cheap goals - one a deflection and one a mistake - but the players gave me everything and I can't fault them."

Rangers manager Steven Gerrard tells his club website: "I don't think we showed our best style in terms of possession and creation, but we've won the game comfortably. We came here to do a job, we came here for three points and we've done it."

What next?
Rangers head for what could be a title-deciding top-of-the-table match at home to Celtic on Saturday (12:30 GMT) before St Mirren visit a Kilmarnock side two points below them in the table (15:00).