New York rain further delays de Minaur's Open progress

New York's lousy weather has dealt Alex de Minaur's US Open title hopes another setback with the top-ranked Australian's first-round clash delayed further by rain for at least an hour.

Former champion Daniil Medvedev and American home hope Alex Michelsen were already safely through to round three before de Minaur even made it on court for his tournament opener.

When he finally opened his campaign on day four, de Minaur looked intent on making up for lost time, racing to a 6-2 4-2 lead over Italian qualifier Andrea Guerrieri in just 49 minutes.

Then the heavens opened again, forcing de Minaur scampering back to the locker room.

The scheduling backlog has left Australia's big hope needing to win seven best-of-five-set matches in 12 days to lift the trophy.

The sixth seed will be hoping the rain passes quickly so he can finish off the 187th-ranked Guerrieri and set up a second-round clash with Dutchman Botic van de Zandschulp.

If he beats Guerrieri, the three-time US Open quarter-finalist will need to be back on site on Thursday (Friday AEST) and again the following day if he wins again.