By Phil Harlow BBC Sport at The Crucible

Higgins trailed 5-4 at the break

Higgins was let off the hook as Day, who hit three centuries in the match, wasted several chances to seal a win.

Day made a bright start before Higgins rallied to 6-6 with two straight frames but three big breaks put Day 9-7 up.

With the match as his mercy, Day missed several crucial potts and Higgins took advantage to force a final-frame decider which he won on the final pink.

The young Welshman was 57-0 up in the 17th frame before a straightforward pink stayed out and gave Higgins a lifeline he gratefully accepted.

In a display reminiscent of Ken Doherty's last-gasp effort's in 2003, Higgins' never-say-die spirit saw him knock in 70, 58 and 68 under the most intense pressure.

I've really never felt pressure like that before, even when I was winning tournaments John Higgins

And the Scot held his nerve at the end of an error-ridden 19th frame to send the match-clinching pink in with a perfectly-judged double.

Higgins described the pressure of beating Day as the most intense of his 12-year professional career.

"Even when I was 9-7 down and he was on a break, I just didn't feel I was going to lose - it's a feeling I've never had before," said Higgins.

"But I've really never felt pressure like that before, even when I was winning tournaments.

"It's only a matter of time before Ryan's up there in the top eight."

Day was struggling to look on the bright side after seeing his chance of a Crucible debut win disappear.

"People are telling me to take the positives but at the moment I feel very disappointed and it's hard to see what the positives are," Day told BBC Sport.

"I scored well but there were a lot of frames where I played scrappy snooker.

"I can play better than I did. I'll take a holiday and chill out, and then practice for next season."

First round result (best of 19 frames):

J Higgins (Sco) 10-9 R Day (Wal)
97-9, 63-10, 52-55, 67-51, 139-0 (131), 21-115 (111), 68-75 (68 Day), 42-73, 29-72 (54), 1-128 (128), 84-8, 57-38 (50), 28-81 (60), 9-112 (112), 70-25 (70), 58-71 (58, 71), 67-58 (57 Day), 68-0 (68), 68-50