Chris O'Connell has crashed Max Purcell's party in the pair's all-Australian first-round US Open shootout in New York.

Purcell had been riding high after reaching his maiden ATP Masters 1000 quarterfinal in Cincinnati, but O'Connell upset the world number 43 to set up a second-round shot at third-seeded former champion Daniil Medvedev.

O'Connell prevailed 6-4, 6-3, 3-6, 7-6 (7/5) in a two-hour, 52-minute battle between the two in-form Sydneysiders.

O'Connell is also enjoying a breakout season, climbing to a career-high 67 in the world last month following a run to the last 32 at Wimbledon.

"I know Max really well, I've known him since he was eight," he said.

"There's a load of Australians in the top 100 at the moment, a lot of Australians playing slams so you are bound to draw one now and then.

"Unfortunately I drew Max but at the same time you look at it there's going to be an Australian through to the second round and that is always a positive.

"So once the first point is played I just feel all that goes out the window. I just look across the net and he is just another tennis player from my point of view."

Medvedev conceded only two games in a 6-1, 6-1, 6-0 first-round rout of hapless Hungarian qualifier Attila Balazs.

But the 2021 US Open champion holds no fears for O'Connell ahead of their show-court match-up on Friday (AEST).

"That's going to be exciting," O'Connell said.

"We had a tight battle this year in Doha, I feel I've got a good game style to maybe cause him some trouble. It was very close in Doha.

"I am sure he has a good idea of what I am going to bring and I'm going to play similar to how I did in Doha.

"But he is a top, top player so I am sure he is probably going to change a little bit from that match."

O'Connell was the only Australian winner early on day two, with five more joining Purcell in crashing out.