Ali, who won his cross-tie yesterday in 11.80 secs, the first sub-12 time electronically recorded in this year's event, powered away from his seven rivals in the final to win in 11.59 and followed 2013 winner Ben Robbins (Edinburgh AC) in striking a blow for youth.
"A brilliant run" said his training partner Leigh Marshall, who won four years ago and might have been a contender this time had injury not struck.
Written off after the heats, from which he progressed only as the slowest of the 10 fastest losers in 12.26 secs, Ali was joint favourite at 4-5 before the final along with Hawick rival Jack Wilson, the fastest of the heat winners on Hogmanay.
"That was just a bad run" said Ali, who works as a waiter and barman in the New Delhi Indian restaurant in Hawick.
"He was tight then, probably due to nerves, but he's done his running this time," said Marshall, who hopes to join Ali in competing indoors at the Emirates Arena this month.
The Dunfermline contenders Gemma Nicol and Kevin Eddie were out of luck, though the latter, the 90-metre sprint winner on Hogmanay, at least had the consolation of a £900 second prize. Nicol, bidding to become the first female winner was controversially excluded from the final by a mere .02 secs when it looked as if she had done enough.
There was a female finalist, however. Jedburgh's Jasmine Tomlinson (21.5m) finishing third in Ali's cross-tie in 12.15 to qualify as a fastest loser.