A dominant second-half showing from Glasgow Warriors delivered a shock 21-16 United Rugby Championship final victory over the Bulls in Pretoria on Saturday.

The Scottish outfit defended and carried the ball tigerishly and were never intimidated by a partisan sell-out 50,388 crowd at Loftus Versfeld stadium.

Outplayed in the first half and trailing 13-0, Glasgow scored a pushover try in first half added time through Scott Cummings, and a George Horne conversion narrowed the gap to six points.

Warriors, making a fourth final appearance in the competition with one previous triumph, outplayed the Bulls after half-time with George Turner and Huw Jones scoring tries.

Horne converted both and his only blemish was a later long-range penalty attempt that fell short.

All the South Africans could manage in reply was a penalty from Johan Goosen, who finished with 11 points from three penalties and the conversion of a Marco van Staden try.

In a frenetic finish, the Bulls forced two line-outs five metres from the Glasgow tryline, but could not score the try that would have brought the teams level.

South Africans played pivotal roles for Glasgow with Kyle Steyn the captain and Franco Smith the coach.

"We had enormous belief and stuck to it when under pressure for most of the first half," said Steyn, who set up the match-winning try for Jones on 63 minutes.

"Our first try at the end of the first half was key and we increased the intensity in the second half."

Bulls captain Ruan Nortje said: "Credit to the Warriors, who are deserved champions. We have no excuses."