A probing spell from NSW product John Hastings has helped Victoria shatter the Blues' unbeaten one-day cricket run despite Shane Watson's return to batting form and a bowling record for Mitchell Starc.
Chasing 245, the Blues looked to be coasting at 2-159 in the 33rd over of Sunday's contest at North Sydney Oval.
Fast medium allrounder Hastings (4-30), who moved to Victoria several seasons ago after failing to break into the NSW senior squad, triggered a decisive collapse of 4-13, in four overs, taking three wickets in that period.
NSW were already guaranteed of finishing first and advancing directly to next Sunday's final after winning their first five games.
Victoria will seal a place in the elimination final if they beat Tasmania in their final round robin game on Tuesday.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
"This was a huge win for us today, " Hastings said after the 21-run victory.
"We were confident going in, but we haven't played our best cricket yet."
Hastings, who has played for Australia in all three formats, was rewarded for bowling straight, with all his wickets - and the Blues first six - falling to lbw decisions.
Watson, who hadn't scored more than 25 in his first four innings, compiled a patient 64 off 91 balls.
"I haven't scored any runs at the start of the tournament, I was just trying to spend some time out there," Watson said.
"I was just trying to get a bit of rhythm into my batting again, which I started to find.
"We thought 244 was definitely very chase-able here especially on a small ground
"It is disappointing, but we've got a week to freshen up."
Watson stressed he wanted to play one-day cricket for Australia.
"I know I've still got a lot of good cricket left in me," he said.
A seventh wicket stand of 47 got NSW to with 27 with 21 balls remaining, but a direct hit run out by Glenn Maxwell from mid-on triggered a final collapse of 4-5.
Rob Quiney (79), playing his first match in this season's tournament, and captain Matthew Wade (63 not out) provided the substance and momentum in the Bushrangers score of 244.
Starc (4-58) took 3-6 of his last 11 balls to swell his competition-leading tally of wickets to 23, eclipsing the previous NSW one-day season best of 21 formerly shared between spinner Stuart MacGill and paceman Aaron Bird.
Two wickets in next week's final will allow him to eclipse the national all-time season record of 25 set in 2008-09 by Victorian quick Shane Harwood, who needed 10 matches, while Starc has only played five so far.
