The pair collided when they went for a catch and medical attention was called for immediately.
After a 45 minute delay, both players were taken to hospital by ambulance and Sussex chief executive Zac Toumazi said: “When I got out there, I just saw two players who were semi-unconcious.
“I didn’t get too close, I just let the experts do what they do.
“In fairness, everybody responded as quickly as possible and the measure that we have in place worked.
“I believe it was exactly the right thing to do to call the match off. Neither side were in any condition to go back out there and play the game.
“I would also like to thank the crowd, they were hugely supportive and it’s just unfortunate that it had to end in this way.
“Our thoughts are with the two guys and we will keep everyone updated.”
Umpire Alex Wharf added: “It was obviously a difficult situation, we just did not see that coming and it’s horrific for the players.
“The main priority for us is the players when something like this happens.
“We want to see them fit and well and no one wants to see things like that happen.
“The players’ safety is paramount so, when a big incident like that happens, it’s not great for the game, so we have to take everything into consideration.
“We spoke to Lord’s and people at the ECB to get a gage of what they are thinking.
“But, from when the incident happened, we almost knew that it would be difficult for us to get back on to the field.”
Sussex physiotherapist John Marrale, who was one of the first people on the scene, said: “Both were unconscious after the collision. Henriques’ was caught by Burns’ knee and Burns had lacerations on the top of his head and below his eye.
“They were given oxygen and pain relief was administered by an intravenous drip before they went to hospital. Fortunately they were sitting up when they left the ground but it was a sickening incident.”
The collision occurred halfway through the 19th over, which was bowled by Tom Curran, when Sussex batsman Steffan Piolet launched a huge top edge into the off side. Henriques and Burns were no more than 20 yards apart when they collided at full pace.
Sussex’s Craig Cachopa, who was batting when the collision happened, said: “It was horrible to see. I don’t deal with those situations well so I came straight off but the decision to call the match off was the right one.”
No one from Surrey was available for comment. A brief statement on their website said: “Rory Burns and Moises Henriques were sitting up and conscious when they left the ground. The game was abandoned with the full consent of both sides.”
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