The Frenchman, who only signed for Caley Thistle on Friday, entered the fray with 25 minutes to go and almost bagged the winner with a low shot which smacked the inside of the post.
St Mirren's Steven Thompson was the visitors' most threatening influence as both teams continued to chase a coveted top-six berth.
It was the first 0-0 draw at Tulloch Caledonian Stadium since Celtic travelled north in February 2009 - and the first scoreless game Inverness have been involved in since January last year.
The stalemate extended Caley Thistle's unbeaten run to seven games in all competitions.
It also left Inverness and St Mirren still locked in a five-team mid-table pile-up in the chase for the top six.
Winger Gnakpa and loan man Sam Winnall - who signed on Thursday - were named on the bench, while injured loan defender Steve Williams was replaced by Ross Tokely in the only change to the side which beat Hearts 1-0 last week.
St Mirren made one switch from to the team who lost 2-0 at home to Celtic last time out, with captain Steve Thomson in for Kenny McLean.
Inverness started brightly as they aimed to leapfrog St Mirren in the table with Shane Sutherland shooting wide early on.
But the early pressure failed to produce anything significant and the visitors almost made them pay when Thompson's low shot was blocked by keeper Ryan Esson.
Jonny Hayes - who has been linked with a move to Celtic - showed his attacking intent by setting up Greg Tansey, who ballooned his shot over the bar.
Esson was equal to Thompson's flicked header when he connected with Graham Carey's cross and moments later Paul McGowan shot wide.
Carey's angled shot from 30 yards flashed past the post after taking a deflection on the half-hour mark.
Hayes continued to be Inverness' only real livewire, the Irishman weaving past challengers in midfield before dragging a shot wide.
Carey shot over from around 20 yards and Thomson forced another save from Esson with a powerful header as St Mirren created the lion's share of the chances.
Kenny Gillet squandered the hosts' best opportunity of the half when he fired wide after Nick Ross' shot was blocked.
Gregory Tade was at the centre of the action after the break.
The Frenchman broke forward and sent a dangerous cross through a crowded penalty area before failing to connect with a Richie Foran cross that was palmed away by Craig Samson.
The 25-year-old then missed from four yards when he stretched to meet a Hayes cross only to guide the ball inches wide.
St Mirren weathered the storm for Carey to send a 30-yard free-kick just wide.
Impressive interplay between Tade and Foran opened up a chance for the Irishman but his shot from outside the box cleared the stand.
Marc McAusland's header was comfortably saved by Esson after Carey's set-up.
Gnakpa - who has signed a short-term deal until the end of the season after leaving Walsall - replaced Sutherland after 64 minutes.
McGowan missed a gilt-edged chance after a lay-off from Thompson with Esson easily gathering his lacklustre shot.
Tokely's header from a Hayes free-kick was straight down the throat of Samson as Inverness freshened up their attack by replacing Tade with Winnall.
Gnakpa almost made an immediate impact when his low angled effort thundered back off the inside of the post after he was found in space by Ross.
Twenty-year-old Ross then sent a golden chance over the bar when he pounced on Hayes' near-post cross.
Gnakpa directed a header wide with five minutes to go after meeting a Gillet long ball.
A strong driving run from Gnakpa saw Inverness flood forward in the closing stages with the 28-year-old playing in Winnall. He found Ross, but he was denied by Samson from close range.
