Hong Kong tennis star Coleman Wong's father says he is very proud of his son's historic victory in the US Open and is happy not only with the result, but also Coleman's resilient performance.

Coleman, 21, became the first Hong Kong, China player to score a victory in the Grand Slam singles main draw in the Open era, stunning American Aleksandar Kovacevic in the first round 6-4, 5-7, 7-6, following a 7-4 tiebreak.

His father Bruce told RTHK on Tuesday that he didn't really have many expectations ahead of the match and simply wanted to support his son by watching the game live in Hong Kong.

But he said it turned out to be a proud moment for his family, and also for many people in the SAR.

"It was really unbelievable for most of the Hong Kong people, like myself. Of course we're very happy, not only because of the result but the performance," the father said.

"In these few months, there were so many ups and downs, a lot of struggles. We're so happy we can see some good results at this moment."

An excited Coleman spoke to his parents a couple of hours after the game, Bruce said, urging them to fly straight to New York to attend the game in the third round if he defeats Australian Adam Walton on Wednesday.

"He asked us, 'why don't we go there to attend the game?' He wants us to go there....and yeah, we're planning to do this," Bruce said with a chuckle.

The primary school principal and his teacher wife said they will do a whirlwind trip for their son, despite being busy with preparations for the new school year.

The father said even though Coleman struggled on grass and clay at Wimbledon and the French Open in recent months, he kept practising to try to overcome his weaknesses.

He said he is proud of his son's perseverance and willingness to make adjustments, and the effort paid off on the hard court at the US Open.

Meanwhile, in a statement released through the Tennis Association of Hong Kong, China, Coleman said the achievement means a lot to him and it is hard for him to describe his feelings.

"Being a tennis player from Hong Kong isn’t easy. On big stages like this, many people think I can't do it. But I'm here to prove that I can," he said.