Georgia coach Milton Haig hailed a "pretty historic occasion" for his players after they toppled World Cup opponents Tonga 17-10 at Kingsholm.
It was only Georgia's third win in World Cup history - Namibia eight years ago and Romania in 2011 were their other scalps - and came following tries by inspirational captain Mamuka Gorgodze and his back-row colleague Giorgi Tkhilaishvili.
With minnows Namibia also in Georgia's World Cup group, which is completed by New Zealand and Argentina, a third-placed pool finish and automatic qualification for the 2019 tournament in Japan could now be achieved.
"This has been four years of planning, four years of work from everybody involved - and largely this squad has been together for the same amount of time with me," New Zealander Haig said.
"It (World Cup qualification) is obviously a focus since we qualified for Pool C, and we knew to have a chance of creating history for Georgia that we would have to win this game today.
"We have taken the first step, but there is still a fair bit to go in this tournament.
"We haven't reached the next level - that's still higher. When you can defeat a team like Argentina, Scotland or Samoa then you can talk about getting there.
"It's about being consistent with your Test wins.
"We're pretty good at winning one or two a year against higher-ranked teams, but our goal is to compete consistently with the top eight teams in the world. There is still a lot of water under the bridge for that to happen.
"Today was pretty historic for everyone involved in Georgian rugby, and we are very pleased."
Full-back Merab Kvirikashvili kicked a penalty and two conversions for Georgia, while Tonga replied with a late Fetu'u Vainikolo try - he became Tonga's record Test try scorer in the process - and Kurt Morath booted a penalty and conversion, yet Georgia deservedly held on after Kvirikashvili was sin-binned during the dying minutes for repeated offside.
It was was also a day to savour for 18-year-old Georgia scrum-half Vasil Lobzhanidze, who became the youngest player ever to feature in the tournament.
Haig added: "This is the best-prepared side ever to leave Georgia, and today we showed that. Fitness-wise, we were able to sustain our defence over 80 minutes, and that allowed us to come away with the win."
Tonga captain Nili Latu had no complaints about the result - and although tournament minnows Namibia are up next for his team, world champions New Zealand and in-form Argentina also remain to be played.
"Credit to Georgia for winning the game," he said. "They disrupted our line-out, and they ground it out really well in the scrum.
"One thing we wanted coming into this game was our set-piece, but it wasn't good enough today. Georgia just kept putting pressure on scrums and line-outs, and it is something we will have to look at.
"We made everything harder for ourselves. We have still got three games, and we have to regroup."
A couple of television match official decisions, meanwhile, went against Tonga, and Latu added: "The TMO is there, and I think we could have more challenges - I don't think we are losing anything.
"Everything was shown in the first game last night (between England and Fiji), and I don't see anything wrong with that."