Defeats for the pair could threaten their chances of competing in this season’s Masters.
Zhou Yuelong and Anthony McGill were each dispatched of as the Northern Ireland Open got under way at the Waterfront Hall in Belfast on Saturday evening.
The duo, who as top 16 seeds had their matches held over to venue stages following last month’s preliminaries, were beaten by Jimmy Robertson and Lee Walker respectively in the round of 128.
Robertson, the former European Masters champion who has been in resurgent form during this disjointed season, opened the tie strongly with breaks of 50 and 70 helping him to a 3-0 lead.
Zhou fought back to trail by only one frame but could not force a decider, as a run of 59 in the sixth frame proved enough to send the Englishman through to the first-round proper.
McGill, meanwhile, was edged in a high-scoring affair with Walker that lasted the distance and boasted six breaks above 50 between them.
The latter compiled runs of 60 and 67 either side of snatching a close second frame on the black to lead by 3-0 against the world number 16.
McGill subsequently fought back and seemed to gain the initiative with contributions of 73 and 137 helping him to retrieve the deficit and lock the scores at 3-3.
However, Walker ultimately held on and a 53 break in the last frame proved to be enough to separate the two competitors in what is the first European Series event of the term.
Elsewhere, it was a much easier time for Chinese teenager Gao Yang, who comfortably saw off the challenge of local amateur wildcard Christopher Clifford with a 4-0 thrashing.
On Sunday, the action will increase with a full day’s play scheduled and the likes of reigning champion Judd Trump, world champion Mark Selby, and crowd favourite Mark Allen among those set to enter the fray.
Away from the baize, Tom Ford was forced to withdraw from this year’s Northern Ireland Open after testing positive for COVID-19.
Live coverage in Ireland and the UK continues on Eurosport and Quest TV.
Click here to view the draw (Times: CET)