England were left fearing disciplinary action against Dele Alli after the midfielder was caught on camera making an obscene gesture during his side's World Cup qualifier against Slovakia.
The Tottenham Hotspur player raised his middle finger during the 77th minute of Monday's game at Wembley, which England won 2-1, and there were claims it was directed at French referee Clement Turpin.
England manager Gareth Southgate played down the incident, saying Alli had been sharing a joke with teammate Kyle Walker, but if Fifa decide to investigate, the 21-year-old midfielder could face punishment.
"I've not seen it, but I've been made aware of it," Southgate said in his post-match press conference.
"Kyle and Dele were mucking about and Dele's made a gesture towards Kyle. I don't know what the angle picked up by the camera is, so I don't know if that is clear [who it was aimed at].
"The pair of them have a strange way of communicating. But that's what they've said when it's been raised."
Alli took to Twitter after the game to corroborate what he told his manager.
"Just to clarify, the gesture tonight was a joke between me and my good friend Kyle Walker!" Alli wrote on Twitter after the game.
"Apologies for any offence caused! Great win 2nite."
It was not clear from footage of the match who Alli had aimed his gesture at.
In a recent precedent, Lionel Messi was given a four-game ban for swearing at an assistant referee during a World Cup qualifier between Argentina and Chile in March, although his suspension was overturned on appeal.
The controversy generated by Alli overshadowed a positive evening for England, who now require two points from their final two group games against Slovenia and Lithuania to qualify for next year's World Cup.
The Group F leaders fell behind in the third minute when a careless touch by Marcus Rashford was compounded by a lapse of attention by the Manchester United forward that allowed Stanislav Lobotka to run in and score.
But Rashford's corner set up Eric Dier to equalise with a deft near-post flick in the 37th minute and Rashford fully redeemed himself by arrowing the winning goal past Martin Dubravka on the hour.
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Southgate praised Rashford for casting his early misstep to the back of his mind.
"It didn't surprise me. Having worked with him, he's such a mature character," said Southgate, who switched Rashford from the right flank to the left flank late in the first half.
"The start surprised me. But the switch of wings was important as well. It allowed him a slightly different defensive role and he adapted very well to that.
"His maturity is excellent. You look at him and he's never in awe of the occasion. He doesn't have any fear of anything.
"I don't think the team did, either, and responded well. He's still a work in progress as we saw at the beginning of the game, but he's getting stronger.
"His impact in taking people on and getting us up the pitch on the counter-attack was huge. He had a huge impact on the game."
While England's path to Russia is now clear, second-place Slovakia's is strewn with obstacles after a result that allowed both Slovenia and Scotland to close to within just a point of them.
They visit Scotland in their next game on October 5 and manager Jan Kozak knows his side's hopes of securing a play-off spot could come down to how they fare in Glasgow.
"Before the double-header against Slovenia and England, we wanted to have the situation in our own hands before the last two games and we still have the situation in our own hands," he said.
"It will be difficult, but we're strong and our quality is going up, so hopefully the result against Scotland will be better than today."