It was an odd ending to an entertaining encounter: a referee collapsing with cramp in added time.There were just a few minutes left of USA’s 2-0 victory over Australia at the World Cup when Felix Zwayer fell to the ground and called for assistance. But just as striking as the injury itself was the remedy: pickle juice, handed to him by Mexican fourth official Katie Garcia.So why did he resort to it and have we seen this before? The Athletic tells you all you need to know.What happened to the referee in the USA-Australia game?In the third minute of second-half stoppage time, German official Zwayer — having just shown USMNT’s Chris Richards a yellow card — went down with cramp, halting the match for over 90 seconds.Referees cramping is unusual, although in this instance it should not have been entirely unexpected. Temperatures in Seattle reached around 28C (82F) on Friday and it was a big occasion, with plenty of scrutiny on Zwayer and his team as the USMNT attempted to secure their place in the knockout phase.After collapsing to the ground, Zwayer, 45, needed assistance from Australia midfielder Aiden O’Neill, USMNT striker Folarin Balogun and his assistant referee, who all stretched his leg out in an attempt to relieve the pain.Felix Zwayer is helped after cramping at the end of the game between USA and Australia (Alex Grimm/Getty Images)The fourth official, Garcia, then sprinted over from the touchline to bring Zwayer a carton of pickle juice, which he took on and swiftly got to his feet.The Seattle Stadium let out an ironic cheer, and Zwayer stretched out his left hamstring before ambling back into action to officiate the remaining minutes of play.