Brumbies coach Stephen Larkham has disputed the crucial dismissal of hooker Josh Mann-Rea after his side's unbeaten Super Rugby record was wrecked by a 31-11 loss to the Stormers in Cape Town.

The Stormers scored three tries to one in the match played early on Sunday (AEDT), though two of their five-pointers came in the last five minutes.

The Brumbies played the last 16 minutes with 14 men after reserve hooker Mann-Rea was sent off for punching front-rower Oliver Kebble.

Larkham's side only trailed 16-11 at the time, but the penalty awarded for Mann-Rea's indiscretion was kicked to give the home team a buffer of more than a converted try.

Stormers winger Dillyn Leyds was then awarded a try despite doubt over whether he had contact with the ball and reserve forward Vincent Koch crashed over from close range right at the end.

Larkham disputed the conclusion of TMO Marius Jonker that Mann-Rea had also used an elbow on Kebble.

He said the dismissal should be sufficient punishment heading into Monday's hearing, after Mann-Rea allegedly contravened the law relating to punching or striking.

"I couldn't see an elbow in there and that was clearly why he was sent off," Larkham told AAP.

"The referee, Jaco Peyper, thought it deserved a yellow card, but the TMO was intent on trying to get him off on a red card.

"We'll have to review it, but there's a element of that we put our hands up for, we shouldn't have been so aggressive there.

"The pleasing thing is the way that we fought when we were down to 14 men."

© Luke Walker/Gallo Images/Getty Images

If Mann-Rea is suspended for next week's game against the Cheetahs in Bloemfontein, the Brumbies will fly Robbie Abel over as back-up hooker to captain Stephen Moore.

The Stormers, who like the Brumbies now have a 3-1 record, did an excellent job of starving the visitors of possession in the home team's half.

The Brumbies created few scoring opportunities apart from winger Henry Speight's try.

"We made some mistakes, our set-piece execution wasn't quite where it needed to be early in the game," Larkham said.

"We fought through that quite well. We just didn't get a lot of opportunities after that."

Larkham said from where he was sitting he felt the try to Leyds should probably not have been awarded.

Speight's try, which was set up by a bust and cut-out pass from centre Tevita Kuridrani, was the Brumbies' only score of the first half, which ended with the Stormers 9-5 up.

Five-eighth Christian Leali'ifano's penalty cut the deficit to one early in the second half, but that blew out to eight following a converted try to flanker Siya Kolisi.

Leali'ifano cut the gap to five with his second penalty on the hour, but the Stormers scored the last 15 points.

Speight will have a bruise near an eye checked out.