World number one Judd Trump was forced to fight back from 3-1 down for the second match in a row to keep his English Open hopes alive, as Ronnie O'Sullivan eased into the third round.

The 31-year-old from Bristol squeezed past Yuan Sijun 4-3 in the second round, just a day after avoiding a shock exit to Louis Heathcote by doing similar.

Trump reeled off breaks of 73, 83 and 67 to claim the final three frames as Yuan failed to pick up a single point.

"Today was a little bit better from 3-1 down. I am happy with the way I ended the game but there were still a lot of missed balls and careless shots," he told the World Snooker Tour.

"He didn’t really do a lot wrong from 3-1, I made three good breaks.

"Hopefully I can keep digging myself out of trouble and play a little bit better next game.

"The form is there, it’s not showed itself in this event, but I’m still battling away. Tomorrow is the big day."

Six-time world champion Ronnie O’Sullivan beat Ryan Day 4-2 to set up a third-round tie against Matthew Stevens.

"I thought I missed a few balls. I played all right I suppose. I probably played better than I felt," said O’Sullivan afterwards.

"It’s weird with no crowds, certain players need an atmosphere to get up for it. When you play a good shot you excite yourself and you don’t need the crowd to get you going.

"But when you are struggling you need a crowd to force you to find something. We’ve got to get used to it."

World number five Mark Allen became the highest-ranked player to be knocked out with a surprise 4-0 defeat against Robbie Williams, ranked 102 places lower, after breaks of 80, 70 and 61 inflicted the damage.

"All credit to Robbie, he played very well and froze me out for most of the match," said Allen.

"I didn’t make too many mistakes. I’ll just have to get back to practice because there are no secret recipes. Hopefully I won’t have too many days like today."

Defending champion Mark Selby trailed 2-0 and 3-2 to China’s Chang Bingyu but Selby made breaks of 74 and 125 in the last two frames to win 4-3.

Ding Junhui had no such difficulties sweeping aside Luca Brecel 4-1 with breaks of 97, 88 and 137.