Jordan Brown’s defence of his Welsh Open crown was ended at the first hurdle after he went down to a 4-3 defeat to Mitchell Mann at Celtic Manor.

Brown, who defied odds of 750-1 at the outset of last year’s tournament to collect the first ranking title of his career by beating Ronnie O’Sullivan in the decider of a gripping final, went 2-1 ahead with a 124 break.

World number 89 Mann, ranked 65 places below Brown, twice battled back to level and then prevailed in the all-important seventh frame to move into the second round, setting up a meeting with English compatriot Ben Hancorn.

Mark Selby defeated Chen Zifan 4-1 to breeze into the last 64, where the reigning world champion will be joined by Judd Trump, Zhao Xintong, Mark Allen, John Higgins, Stuart Bingham and Mark Williams, all of whom also won 4-1.

A break of 121 was the highlight for Neil Robertson as the Masters champion thrashed veteran Jimmy White 4-0 while Barry Hawkins hammered Switzerland’s Alexander Ursenbacher by an identical scoreline.

Stephen Maguire, champion in 2013, lost the final three frames as he crashed to a 4-1 loss to Fergal O’Brien while Kyren Wilson was pushed all the way by Dominic Dale before eventually coming out on top 4-3.

Zhang Anda edged out Anthony McGill 4-3 while there were also wins for Shaun Murphy, Yan Bingtao, Iulian Boiko and Elliot Slessor.