He posted his record lap towards the end of the race after Northern Irishman Michael Dunlop had twice lowered the mark, but had left his run too late and had to settle for fourth overall.
Anstey has a habit of starting his race at his own pace and then easing into it, increasing his speed as the race progresses.
"I don't know why but it took me ages to get going," he said. "That last lap was a really good lap and it could have been a bit quicker, but I'm really pleased and the bike's looking good."
Anstey had his work cut out during the race, dropping outside the top 10 on the first lap after overshooting the Nook and having to heave his bike around to get back on to the course.
He soon had his head down and flew around the course, hauling himself back up through the field to finish just off the podium.
The star of the 2011 movie TT3D: Closer to the Edge, Guy Martin, finished a close second to Dunlop and, after 10 years, at the time of going to press, was chasing his first TT win.
The Lincolnshire racer has had 14 podium finishes at the Isle of Man, , but has yet to win.
"I love riding my bike, but I'd like to be riding it a little bit faster than we did today," Martin said after Wednesday's Supersport race. "There was no lack of effort on my part, but it is what it is."
The speeds the riders reach on narrow, off-camber and bumpy public roads defy belief.
It is a track on which the smallest of mistakes can be fatal - there have been more than 249 fatalities, including one this year, on the Isle of Man TT course. Seven New Zealanders have been killed since 1911.
Gone are the days when regular Grand Prix riders used to make the annual sojourn across the Irish Sea to risk life and limb. These days it's only the hardy, or in some cases the plain foolhardy, who hurl themselves around the narrow country lanes at breakneck speeds.
"The Isle of Man is all about experience," Anstey told the Herald in an earlier interview.
"Every year you're still learning little bits and pieces - there might be some new tarmac somewhere or it could be a bit bumpier than last year. So it does vary from year to year.
"You definitely need the experience around this place to do well and know where everything is."
One lap is a long and arduous 60km and races take up to an hour and three quarters. Remembering every corner over that distance is a feat in itself.
"It's not easy but it's all down to experience," said Anstey. "You've got to do as many laps as you can really. A lot of guys when they get here go straight out and go a bit crazy.
"Whereas I build my speed up slowly over the week and make sure my lines are all spot on. The speed then just comes."
Results
Bruce Anstey at Isle of Man:
TTs contested: 20 (1996-2000, 2002-present)
TT wins: 9
First TT win: 2002 250cc TT
Most recent TT win: 2012 Supersport TT, Race 1
Podium finishes: 31
