The Scot is considered one of the most talented players in the game but he has not been able to translate that into major trophies.
This year he has fallen outside of the top 16 in the world and had to qualify just to reach the Crucible Theatre.
He had trailed 6-3 after Saturday's opening session, when Maguire felt his opponent was "there for the taking", but grasped a lifeline when the Glaswegian front-runner became jittery.
"I will now float around the top 32 for the next few years without breaking into the top 16". It's hard to accept but it is accepted.
"I think I'm going to live until about 200 now, I feel so good", he said.
Maguire squandered chance after chance to assert his dominance of the contest yesterday, and an O'Sullivan victory began to look an inevitability long before he crossed the winning line. But Maguire was far from settled and a badly-judged blue missed its target, allowing O'Sullivan to take the lead.
"The hunger is there, I will fight to the death".
"I am never hungry, I have masses amounts of energy and I just want to help as many people as I can and compared to the average Briton I will always look well because we are an unhealthy country".
11-year-old bought as bonded labourer — Surat rape case
The body of the minor girl was found in Surat's Pandesara area on April 6 with 86 injuries, including on the private parts. The autopsy report suggested the girl was raped and tortured over eight days before being strangled to death.
"I still enjoy it".
"I have tried all sorts of diets and if you don't get it right then you can feel really bad". I know this one works and it will work for everyone.
"That match was there for the taking but he's finished me off in the end quite convincingly".
"Once it went 6-3, I was happy but I think he would have been delighted".
"I was really gutted because they took a Saturday afternoon to watch some snooker and thank God Stephen potted some balls". When they play well they are awesome, I do not have that. "You just want to battle though and I feel very lucky to be in the next round now".
In other action, two-time runner-up Ali Carter came from behind to see off 2006 champion Graeme Dott 10-8, while Kyren Wilson beat Matthew Stevens 10-3.
"The biggest thing for me this year has been how I've tackled how I eat. I was missing balls all over the place".