"From my side I'm very angry. There will be consequences because of this performance. I won't go through yet what those will be. It reflects on me."
Asked about his future, he merely said: "We'll look at everything."
The islanders bagged the only two tries in a frantic encounter, with the home brigade failing to impose any real authority.
And with Scotland also facing a nightmare World Cup draw thanks to their recent dreadful displays, Murrayfield chiefs must now decide if Robinson is the right man to stay at the helm for the Six Nations campaign.
The Tongans came out with all guns blazing and their rousing early endeavours resulted in five-eighths Fangatapu 'Apikotoa banging over a penalty.
His opposite Greig Laidlaw replied with a penalty kick of his own in the 11th minute and hooker Scott Lawson was then driven over the line in the wake of a well-executed rolling maul, but the video referee ruled he had failed to ground the ball.
Eight minutes of constant pressure yielded nothing for the home men
Having failed to breach the visitors' defence, Scotland resorted to the boot as Laidlaw's penalty gave them a 6-3 halftime lead.
The crowd volume rose when Sean Lamont bashed his way down the middle to create a clear-cut chance. They couldn't turn the good work into a touchdown, but collected another three points from Laidlaw's accuracy.
The contest burst into life in the 51st minute as Tonga snatched a surprise lead.
Lock Lua Lokotui more than made up for his first-half yellow card by burrowing over for a try from point-blank range, giving 'Apikotoa a simple conversion.
Tonga 21
Scotland 15
-AAP
