The only contest between these sides this season ended goalless in August.
Motherwell had 66% possession that day but lacked a cutting edge, injury issues meaning they played without a centre-forward.
St Mirren had the better of the chances, but the stalemate means they have won only two of their past 16 league meetings with the Lanarkshire club and are winless in six.
Motherwell may be four points better off in the Premiership and in better form but this feels like a 50-50 affair.
The Fir Park club have won four of their past six matches, including their quarter-final success at Aberdeen.
Across 10 league games, they have scored double the goals of St Mirren (16 to eight) but conceded one more than the Paisley side (13 to 12).
In left-back Emmanuel Longelo and midfielder Elliot Watt, both signed in the summer, Motherwell boast two players who are among the standouts in the Premiership so far this term.
St Mirren, meanwhile, have won once in five matches since dumping out Kilmarnock on penalties in the last eight.
But an impressive showing against league leaders Hearts in midweek showcased all the redeeming features in Robinson’s side, who posed a serious threat from set-plays.
“Really contrasting styles between both sides,” BBC Scotland pundit Neil McCann said on Sportscene.
“If Motherwell get a grip of the game, it’ll be difficult for St Mirren. You could see St Mirren going old school and making Motherwell defend direct balls like they did against Hearts.
“I lean towards Motherwell because of the big pitch at Hampden. I make them favourites. But the way Robinson gets his teams to play, he will come up with a game plan to nullify space.”
