In a tournament full of surprising incidents, there was another unusual moment when debutant referee Felix Zwayer fell victim to the heat on Friday.Before Australia suffered a 0-2 loss to the United States, Zwayer fell to the ground after being overcome by the conditions.The German referee seemed to be in a lot of pain during the stoppage time. The players had to endure an extra six minutes of delay after a severe spasm hit the referee.“Oh, here we are. I’ve seen it all now. The umpire’s got a cramp,” former Australian right-back Luke Wilkshire said in commentary.“It’s the first time I’ve seen a player help the referee in that way,” added broadcaster David Basheer, referring to the moment Australian defender Aiden O’Neill stepped in to help Zwayer stretch out the cramp.The cameras remained focused on the referee as he was offered a drink to help him recover. Standing right next to the touchline, assistant referee Katia Garcia quickly rushed over with refreshments.Watch:Garcia was also seen warming up and seemed ready to take Zwayer’s spot if the situation called for it.After being helped and aided by the players, Zwayer took the whistle and got back on his feet. He finished the rest of the game as the incident added another memorable chapter to this World Cup.Although Zwayer has officiated on some of football’s biggest stages, including the Bundesliga and UEFA Champions League, Friday’s group stage match marked his first appearance at FIFA World Cup.Co-hosts USA, meanwhile, had little to complain about as they secured a 2-0 win over Australia to book their place in the knockout stages, joining Mexico in advancing from the tournament on a hot summer afternoon in Seattle.