Georgia overcame a deficit of five places in the world rankings to see off Tonga 17-10 at Kingsholm after a heavyweight clash in Pool C, which also features RWC 2015 favourites New Zealand.
The Tongans edged ahead with an early penalty from Kurt Morath. Merab Kvirikashvili levelled, at 3-3, with another penalty, inspiring a sustained spell of pressure which culminated in a try for Mamuka Gorgodze. Georgia's giant number eight and captain stretched out a long arm to score beside the posts after 28 minutes following a TMO review.
Tonga thought they had scored a try a minute before half-time but referee Nigel Owens ruled that the pass to Salesi Ma'afu had been forward.
Georgia extended their lead to 17-3 in the 57th minutewhen flanker Giorgi Tkhilaishvili finished off a move that he had helped instigate with a try close to the left touchline which Kvirikashvili converted.
Tonga responded with a furious assault on the Georgia line but suffered more disappointment as Siale Piutau failed to ground a grubber kick. Fetu'u Vainikolo scored a converted try in the corner to cut the lead to seven points but they could not add to it.
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