Scotland head coach Scott Johnson was furious with fourth official Gerrie Coetzee following the 30-17 loss to South Africa on Saturday.
Johnson was speaking about an incident involving Jim Hamilton - when the second-rower was shown a yellow card for a push which happened in front of referee Roman Poite and his assistant Neil Hennessy with neither taking action.
"I am bitterly disappointed. I believe we could have won and would go as far as to say that I think we should have," Johnson said.
"There was a 10-minute period where we were down to 14 men and we're not playing tiddlywinks. I've never seen someone sin-binned for that before.
"It was ridiculous. I was watching a game of rugby where you saw that kind of thing right the way through. That was nothing but embarrassing."
Scotland scrum-half Greig Laidlaw felt there were plenty of positives to take from the match though.
The injury-weakened Scots led for much of the game at Mbombela Stadium and were in contention until the final minute when centre Jan Serfontein touched down.
Stand-in skipper Laidlaw, who took over the role after flanker Kelly Brown sustained a tour-ending injury against Samoa last week, was happy with the way the players adapted to the challenge.
"The positives include the new caps sticking their hands up with good displays, and our pre-match plan to slow South African ball down at the collisions worked well," Laidlaw said.
Scotland will now play face Italy in Pretoria next Saturday for third place before the Springboks tackle physically formidable Samoa in the climax of the three-week event.
Springboks centre and skipper Jean de Villiers also praised the Scots for a gutsy display, but admits the team will have to step up a gear when they take on Samoa.
"I am happy with the result but not the performance," said de Villiers. "But let us give credit to Scotland for slowing the ball at the breakdown.
"We showed good character to eventually get our act together and win easily in the end, but are going to have to up the ante to defeat the Samoans next weekend."