The coach had never lost in five outings at Hull FC.
But when the home side scored three tries in eight minutes to reel in the Warriors’ lead, he must have feared that run was about to come to an abrupt end.
With FC leading 24-20, Josh Charnley swept over in the corner to lock the scores and give the Warriors hope.
The intrigue and tension were dialed up as the clock ticked down, as Smith and Marc Sneyd exchanged drop-goals to keep matters level.
Then, with 105 seconds remaining, Smith’s second one-pointer sailed between the uprights - and they hung on for their fourth straight win this season.
It was a dramatic final quarter to a game which had ebbed and flowed and, in truth, been rather average as a spectacle for an hour.
Wigan had produced a solid, efficient display and taken their chances well to take a 20-6 lead.
Wane had labelled his team as the underdogs in the build-up - and their challenge was magnified before kick-off when captain Sean O’Loughlin was ruled out due to an infected cut on his knee.
With Willie Isa, Dom Crosby, Micky McIlorum and the Tomkins brothers also sidelined, it meant Wane was down to his last 17 players with Super League experience - which included a place for centre Oliver Gildart on the bench.
Hull FC, edged out against Castleford a week earlier, boasted NRL recruits Sika Manu and Carlos Tuimavave but their biggest signing, prop Frank Pritchard, was absent.
Ben Flower showed terrific leg-drive to power over through a congested defence from short range in the second minute, and Smith hit his first conversion.
The visitors were then forced to spend a lot of time inside their own half. But a well-organised defence - married with Hull’s clunky attack - preserved their six point advantage.
That was until they risked a shallow kick inside their half which sailed out before Charnley could reach it and, from that position, FC worked their way towards Wigan’s line and Steve Michaels squeezed over in the corner.
Sneyd’s conversion locked the scores 6-6.
With the bulk of the play inside their own half, Wigan were grateful for a pressure-relieving penalty which piggybacked them down field and allowed them to challenge FC’s line.
And they made the chance count, as George Williams’ step and pace opened up a gap in the middle, and he plunged the ball down near the sticks.
Smith kicked the conversion and added a penalty on the half-hour to make it 14-6 in their favour.
Prop Taulima Tautai was spoken to for a spear tackle on Jordan Thompson - predictably, his every touch was booed by the home faithful, who felt the infringement deserved a card.
Wigan weren’t brilliant at the start of the second-half but they were better organised and disciplined. And they turned that superiority into points in the 54th minute when Tuimavave allowed Smith’s bobbling grubber to slip between his fingers, and John Bateman had the simple task of diving on the loose ball.
At 20-6 up approaching the hour-mark, the travelling faithful could have been forgiven for celebrating.
But FC turned the game on its head with three tries in an eight-minute spell to take a 24-20 lead.
First, Leon Pryce rounded George Williams to slide over. And buoyed by that score, they ratcheted up the tempo to register tries down their right side from Manu and Michaels.
Wigan still had time to rescue the two points, and - helped by a penalty - they strolled down field and spread the ball crisply to the left, where Charnley slid over to level the scores.
Smith’s difficult conversion attempt was off-target but, in the resulting set, he struck a fine drop-goal from 30m out to inch them back ahead.
That was cancelled out by Sneyd but in a frenzied finish, Smith stepped up and his another one-pointer, which proved decisive.
Hull FC: Shaul; Michaels, Logan, Tuimavave, Talanoa; Pryce, Sneyd; Taylor, Houghton, Watts, Minichiello, Manu, Ellis. Subs: Green, Thompson, Bowden, Washbrook.
Wigan: Tierney; Charnley, Gelling, Sarginson, Manfredi; Williams, Smith; Flower, Powell, Sutton, Farrell, Bateman, Burke. Subs: Clubb, Mossop, Tautai, Gildart.
Referee: Ben Thaler
Starman: Matty Smith