St Mirren's hopes of leapfrogging Inverness remain alive after mustering a point against their 10-man rivals.
Craig Brewster's side had the better of the opening exchanges and Romanian striker Marius Niculae hit the post.
Saints were handed the initiative early in the second half as Inverness defender David Proctor saw red for a foul on Craig Dargo.
St Mirren could not make the extra man count, but three points against Rangers on Monday would seal ninth position.
Proctor was in trouble with referee Eddie Smith as early as eight seconds in, when he picked up a booking for fouling Dargo.
From the free-kick, Ryan McCay's shot was dealt with comfortably by home goalkeeper Michael Fraser.
Inverness striker Dennis Wyness, who will make a summer move to St Mirren once he becomes a free agent, then failed to find the target with a headed chance.
The home team threatened again when Don Cowie's shot was turned away for a corner, which they could not capitalise on.
Dargo had been prolific in his spell with Inverness and great things were expected of him at St Mirren.
However, he was getting little joy on his return to the Caledonian Stadium and was caught offside as he looked to penetrate the home defence.
His replacement at Inverness, Niculae, went close for the hosts with one opportunity and soon afterwards shot over the St Mirren bar, but neither side could muster a goal before the break.
Billy Mehmet and Stephen O'Donnell caused Brewster's men some concern with early strikes in the second half for St Mirren, but Mehmet cleared the bar and O'Donnell's shot was parried by Fraser.
Niculae then headed wide from Barry Wilson's corner as the hosts looked to reassert themselves, and Cowie was the next man to miss the target.
Proctor had avoided a red card for his early challenge on Dargo, but a professional foul on the same man saw him ordered off in the 54th minute, with Andy Dorman firing over from the free-kick which followed.
MY SPORT: DEBATE
David Barron saw yellow for a crude challenge on Imrie, before Wyness waved farewell to the club as Brewster withdrew him in the 57th minute and brought on midfielder Ian Black to give the 10 men a more solid look.
Home defender Ross Tokely spurned a headed chance from Wilson's next corner, and soon afterwards went into the referee's book for fouling Dargo.
St Mirren failed to test Fraser in the home goal in the closing stages, and Inverness must watch and wait to see if Gus MacPherson's men can jump above them on Monday.
Inverness CT: Fraser, Tokely, Proctor, Hastings, McBain, Wilson (Hart 79), Duncan, Cowie, Imrie, Niculae (Bayne 72), Wyness (Black 57). Subs: Malkowski, McAllister, Kerr, Vigurs.
Booked: Proctor, Tokely.
Sent off: Proctor.
St Mirren: Howard, Barron, Haining, Potter, McCay, Dorman, Mason (Hamilton 72), Murray, O'Donnell, Mehmet, Dargo. Subs: Smith, Docherty, McGinn, McAusland, Crighton, Burns.
Booked: Barron, O'Donnell.
Referee: E Smith.
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