But if it had been awarded, he would not have had the opportunity to be the hero with a game-winning penalty in the final seconds.
Gilbert was denied a stunning start when he celebrated a try after just three minutes only for it to be ruled out by the television match official, who decided the ball had been placed on a defender’s hand and not the grass.
"Yeah, I scored that try," Gilbert said after the game.
"I was a bit confused how someone’s hand could be that huge."
His moment would come right at the death when, with scores level at 17-17, the Highlanders were awarded a penalty about 27m out.
It might be one of the most important kicks of Gilbert’s career as it has kept the Highlanders alive in their bid for a Super Rugby Pacific playoff spot.
He has been kicking superbly off the tee this season — the Highlanders have the highest success rate in the competition — and his shot never looked like missing.
The strapping fullback turned midfielder acknowledged it was the most significant kick of his professional career.
As for his positional change, and whether it might become permanent, Gilbert was nonplussed.
"I’m happy just to play 80 minutes, and to really build consistent performances off that has been really pleasing.
"It’s different. The couple of games I’ve had there haven’t really been games where I’ve been able to inject myself into the game. Today got really disjointed. I guess we’ll see. I’m enjoying it."
Gilbert’s penalty was a nice touch of late drama in a game that never reached any great heights.
Both teams were guilty of some basic errors, and the set piece was a bit of a shambles.
The Highlanders did some nice work at times but they are still lacking the sort of consistency they will need if they are to squeeze into the top eight.
At least, in Gilbert, they know they have a deadeye should either of their remaining games come down to kicking.
The Highlanders had been reasonable value for their 14-7 halftime lead, though both teams were guilty of wasting some decent opportunities.
The Highlanders made all the early running and, after the disallowed try, finally got some reward in the 14th minute.
Several players nudged close to the line, Freddie Burns made a hot-potato pass, Gilbert flicked it back and Garden-Bachop was on hand for the try.
At the other end, the Rebels turned down an easy penalty attempt in favour of the lineout drive, but the Highlanders’ defence was immense.
The Australians had their moment shortly after when captain and No8 Richard Hardwick hurled himself over from a lineout move.
It was a half more about efficiency and physicality than creativity, but Highlanders talisman Jona Nareki had a sniff from a turnover before team-mate Sean Withy was bundled into touch.
The home team finished the half strongly and there was a try for prop Ethan de Groot — such a popular figure, and fizzing to get involved after being rested last week — and an entertaining run from Withy after a kick-off turnover.
A bit of niggle early in the second half was followed by two Highlanders lineout steals, but every time the home team looked like scoring again, something would go wrong, from scrum penalties to breakdown turnovers.
The Rebels gained parity when midfielder Stacey Ili slipped through some ineffective defence, and took the lead for the first time with a Reece Hodge penalty.
Someone needed to make a move and it ended up being the referee, dipping his hand into the pocket to send Rebels hooker Jordan Uelese to the bin for an early tackle on Garden-Bachop.
Gilbert made it 17-17 with a penalty, and the Highlanders thought they had scored with five minutes to play, only for the TMO to spot that replacement flanker James Lentjes held been held up.
The Rebels were on the attack in the final couple of minutes but the Highlanders held firm, before heading back down the right end and working on getting Gilbert his opportunity.
Super Rugby Pacific
The scores
Highlanders 20
Connor Garden-Bachop, Ethan de Groot tries; Sam Gilbert 2 con, 2 pen
Rebels 17
Richard Hardwick, Stacey Ili tries; Reece Hodge 2 con, pen
Halftime: Highlanders 14-7.
