Not of fans or players suffering racist abuse — a fear that had dominated the run-up to the tournament in Russia -- but world governing body FIFA's use of the Video Assistant Referee (VAR) system.
"It is the biggest change in association football for a very, very long time," former Premier League referee, Chris Foy told CNN Sport. "This has to be done right."
Except the Confederations Cup provided plenty of evidence of how VAR got things wrong — notably in not determining Chile defender Gonzalo Jara should have been red carded for elbowing German forward Timo Werner in the face in Sunday's final that was won by Germany.
It was the final straw for many footballers and fans alike.
Serbian referee Milorad Mazic asked for a video replay, as it was a crucial moment; one that could well define a cup final. Nearly three minutes passed before a decision was reached — the foul was a yellow card offence; triggering bewilderment among onlookers.
"In other words, it's s**t?" tweeted former England international Alan Shearer in his less than complimentary analysis of VAR.
VAR has its backers, none more prominent than FIFA supremo Gianni Infantino, who has publicly supported the use of video replays and looks set to implement the system at next year's World Cup.
Sanctioned by the International Football Association Board in March 2016, as part of a two-year "live experiment," VAR applies to four key decisions -- goal, or no goal; penalty, or no penalty; direct red cards (not second yellows); and cases of mistaken identity.
The original mandate stated that the aim of VAR was two-fold -- to achieve 100% accuracy, whilst not "destroying the essential flow" of the game.
Foy is a supporter of the use of technology.
"The beauty of VAR is, that as a referee, if you make a call that's wrong, you would suffer from that, you'd hurt and wouldn't be happy with yourself. VAR could probably take that away."
The final wasn't the only time that VAR courted controversy during the Confederations Cup.
The semifinal between Chile and Portugal was locked in deadlock, when deep into extratime, Portuguese defender Jose Fonte appeared to clearly foul Francisco Silva in the box.
But referee Alireza Faghani signalled play on, VAR was not consulted and therefore did not intervene to reverse a decision that would arguably fall under its purview.
That incident did leave Foy scratching his head.
"It was classic example of people asking why VAR wasn't used; I was surprised we didn't see some intervention on that one."
During the Confederations Cup, VAR also exposed football fans to the kind of stoppages typically seen in rugby, cricket and the NFL.
"Football isn't rugby and rugby isn't football." added Foy, a veteran of FA Cup, Community Shield and League Cup finals.
"Everyone loves the rumbustious nature of football, the tackling. What we don't want to see is the interruptions."
However, former Arsenal and England defender Lee Dixon described VAR as a "shambles" in comparison to those other sports' use of technology in helping to make key decisions.
"If you look at sports that use VAR -- we're the laughing stock," Dixon told ITV.
While the Premier League has no plans of introducing VAR next season, the Bundesliga
are adopting the technology.
Speaking about the possibility of VAR being implemented in English top-flight matches, Foy said: "We are good to go for it. I'm looking forward to this season, with one eye on what's happening in Germany, to see how it pans out over there.
"It is a massive learning curve for us at the moment. I don't think we've got the finished package yet, there's still a way to go," Foy added.
While VAR has polarized opinion, it appears to have the backing of FIFA and the IFAB. If it's inclusion at the 2018 World Cup looks like a foregone conclusion, the system does raise questions about the changing role of referees in football.
Foy is adamant that the use of technology helps emphasize a referee's authority rather than undermine it.
"Their role does not change; because if it does, referees will lose their skill set. The whole thing will lose credibility."
In times where the use of VAR has undoubtedly raised more questions than answers, it remains to be seen how football's governing bodies manage the historically uneasy nexus of referees and technology.
Foy remains unfazed, insisting that his colleagues needn't worry about football's changing landscape.
"They will go out on a match day and referee a football match, no matter what. The rest of it takes care of itself. "