The USA clash against Australia was delayed after the referee went down injured.
With just seconds to go, Felix Zwayer dropped to the floor with cramp and struggled to get up.
In the blazing heat in Seattle, and with a fast paced game, the official struggled to continue.
He was helped by both USA and Australia players, lifting his leg in the air to ease his pain.
But another female official was spotted running on the field to hand him a drink.
Fans flocked to social media to find out what the mystery beverage was.
“What was that the referee was handed?”, asked one.
Another added: “What is that mystery drink?”.
He was able to continue after necking the drwink.
The USA went on to win the Group D World Cup clash 2-0, sealing their knockout stage spot.
And The Sun understands it was pickle juice, known to help relieve cramp, which cured the ref.
The drink relieves muscle cramps in under 60 seconds because the vinegar triggers a sensory reflex in the back of your throat.
This neurological reflex immediately signals your brain to calm the misfiring nerves that are causing your muscles to contract.