Ford won a scrappy opening frame before O’Sullivan, who won the Masters in London last month, reeled off four in a row with a top break of 101. He now meets Mark Davis in the last 64 on Wednesday evening.
Judd Trump looked in fine form as he saw off Andrew Higginson 4-1 with top breaks of 102, 52, 140 and 56.
“I feel like I am scoring well,” said six-time ranking event winner Trump. “I made a couple of centuries which shows I’m playing well, my positioning is good and I’m not making mistakes. I think my game is as good as anyone’s at the moment.
“This is close to home in Bristol. I get a lot of support down here and it would be nice to go well and get to the final. It is always a good atmosphere here, it is real snooker fans.
“I think a higher ranked player will win this one. Mark Selby is due one, Neil Robertson will start to get a run together, and Ronnie O’Sullivan is always dangerous.”
World Champion Selby also eased through, beating Liam Highfield 4-0 with a top run of 89.
“I haven’t done well in the last few tournaments so I’m keen to get back on track,” said world number one Selby. “You are bound to have a few blips during the season – and I’ve lost to players in very good form in the last few events.”
China’s Ding showed his appreciation for his fans in Cardiff
World number five Ding Junhui suffered a 4-2 reverse against Finland’s Robin Hull, whose top break was 84. Despite defeat, Ding spent time after the match signing autographs with a group of around 40 Chinese fans from Cardiff University.
Home favourite Mark Williams was another top 16 star to suffer a first round exit as he went down 4-3 against world number 115 Elliot Slessor. Williams came from 3-1 down to 3-3 before Slessor compiled an excellent run of 90 in the decider.
Slessor: best ever win
“That is without a doubt the best win I have had in my career by a long stretch,” said Gateshead’s 22-year-old Slessor. “To win on TV against a player of Mark’s class has to be number one for me. It is nice to know you can hold yourself under pressure and take chances when you have them.”
A dejected Williams said: “Rubbish, that is how I sum it up. Overall it was so bad, it was frightening. How I am in the top 16 I will never know. I am a shadow of the player I used to be and that’s why I put performances in like that, I am not that good anymore. At this minute I could chuck this cue and not see it again.”
Anthony McGill made a superb 58 clearance in the deciding frame to edge out Masters finalist Joe Perry 4-3.
Two days after his Ladbrokes World Grand Prix triumph, Barry Hawkins kept his momentum going with a 4-1 win over Fraser Patrick. Marco Fu made breaks of 58, 75, 93 and 57 as he came from 2-0 down to beat Martin Gould 4-2.
China’s up-and-coming Yan Bingtao continued to impress as he beat Daniel Wells 4-1 with a top run of 68, while Mark Allen saw off Sydney Wilson 4-0. Brazil’s Igor Figueiredo scored one of his best career wins as he thrashed Alfie Burden 4-0.
Jamie Jones won a Welsh derby against wild card Tyler Rees 4-1, while Coral English Open winner Liang Wenbo beat Rod Lawler 4-2.
Another Welsh derby went the way of Michael White as he beat Duane Jones 4-1 with a top run of 72.
“There is a lot more snooker to come from me,” said Neath’s White. “I am working so hard in practice, I am playing the best snooker I have ever played and I am really enjoying it. My mind and game is definitely better than last year. I am hoping for a big week here so I am looking forward to round two. I know my game is good enough to beat the top players, it is just consistency over a week.”