FIFA formally approved video review to be used at this summer's World Cup.
The last step towards giving match officials high-tech help in Russia was agreed in Colombia on Friday by FIFA's ruling council, chaired by President Gianni Infantino.
"We need to live with the times," Infantino said at the meeting.
"We are going to have our first World Cup with VAR. It has been approved and we are extremely happy with that decision.
"It's an essential, important and historic decision, based on the meeting of IFAB two weeks back. It's a decision based on trials, carried out in over a thousand matches that provided us with guarantees and facts that VAR helps referees."
The decision comes two weeks after FIFA's rule-making panel voted to write video assistant referees (VAR) into the laws of the game.
FIFA Council member Reinhard Grindel wrote on Twitter that clear communication will be important to make the system a success.
Referees can call on VAR to review and overturn "clear and obvious errors" plus "serious missed incidents" involving goals, penalty awards, red cards, and mistaken identity.
"We have been working at this for two years with a group of referees and experts," Infantino added.
"We have looked at the technology to be ready for the World Cup."
Infantino said no one on the FIFA Council was against the decision, and added: "We didn't take it lightly. We studied it thoroughly for two years.
"I was sceptical at the beginning but without trying things you can't know what they are worth. That's why we carried out trials in those 1,000 matches. There are facts: referees make one important mistake one in every three, with VAR it is every 19. These are facts and figures.
"The success rate of referees today without VAR is 93 percent, which is already excellent. With VAR they reach 99 percent. We need to leave one percent, we cannot provide 100."
Infantino added that time-wastage had been discussed "passionately" but concluded: "It's not possible that in 2018 everyone in their living room knows a few seconds after the play whether a referee has made a mistake and the referee doesn't."
Infantino had acknowledged two weeks ago that VAR was currently "not perfect" after rules panel IFAB met in Zurich.
In 18 months of trials worldwide -- including at the 2017 Confederations Cup in Russia, Bundesliga, and Serie A -- reviews have often been slower than promised and communication has been unclear in the stadium.
Controversy has been stirred even by the most experienced VAR officials who have handled many more games than most referees who will work at the 64-game World Cup.
A total of 36 referees, plus their teams of assistants, are being trained by FIFA for World Cup duty and many come from countries which do not use video review in domestic games.
FIFA will now look to sign a World Cup sponsor for video review at the June 14-July 15 tournament.