The surface has been in a terrible state because of heavy rain before Tottenham played Sunderland in the Barclays Asia Trophy last Wednesday.
More rain fell on Sunday, though the efforts of Spurs groundsman Darren Baldwin at least ensured the tournament was completed on time with Manchester City beating Sunderland in the final.
Baldwin has now flown home, and United will play the final game of their five-match pre-season tour against Kitchee FC on Monday evening.
Moyes was present to watch Spurs' game and he cancelled a planned open training session with the aim of protecting the pitch.
But he insists the show must go on, and the fixture will be fulfilled.
"Two teams have to play on it," Moyes said. "It is the same for everybody. We are used to playing on good surfaces and pitches but there was nothing the people in Hong Kong could do to make the weather any better. It was terrible for three or four days.
"It is drying out now, which might make it worse if it gets bobbly."
England international Phil Jones agreed, whatever the state of the pitch.
"I am not sure what the worst pitch was that I have played on," he said. "No matter what is presented to us, we are ready to play."
Spurs boss Andre Villas-Boas blamed the pitch for the ankle injury suffered by Jan Vertonghen which makes the defender a doubt for their season-opener at Crystal Palace on August 18.
But Moyes said: "Players can get injured on good pitches as well. We would rather be on a very good surface. That is obvious."
Sunderland's Craig Gardner has warned a sell-out 40,000 crowd not to expect free-flowing football.
"The pitch was absolutely horrendous," he said. "It wasn't bad enough for the game to be cancelled, but it was soft. It was dead.
"You couldn't pass the ball forward because it wasn't rolling properly and you were scared in case you passed it inside in case it stopped rolling. You had no choice but to hit it long."