First to turn was the limit group in which veteran Laurence Sunde was going strongly, with good contributions from Curtis Weir, Laurika Hazlehurst and the experienced Brian Scott.
Making ground immediately behind them was a strong looking bunch which included Marcia Goode, top young track rider Cassie Cameron and competitive lightweight veterans Allan Luff and John Black.
They had reduced the group's gap to two-and-a-half minutes as turn marshall Ron Cheatley sent them back towards Wanganui.
However, looming ominously were the second break riders, being driven along at high speed by Tucker, Brian Scrimshaw and Rob Gemmell with Jason Bardell also putting in some decent turns.
Chasing hard behind them, but struggling to make up the leeway was a very handy break group featuring Steve Cowan, Boaz Darby, Lewis Bunker, Richard Stanton, and former Olympian Gary Anderson.
Further back, young Matt Goode was riding out of his skin and out-climbing his scratch group companions, including Phil Groves, Pat Johnstone, Jason Sturzaker and Adam Gosney.
Tucker and company caught the two groups ahead of them just before the descent back into Waitotara, and the newly-formed front bunch stayed together until the decisive climb out of that valley when major gaps opened as the stronger riders accelerated, including Cameron, Luff and Black.
Tucker also dropped off and with almost 100m between him and his erstwhile companions, the chances of a podium finish appeared gone.
Remarkably, he showed great fortitude and time-trialled back to the leading bunch and after a short period of recovery he was once again on the front, forcing the pace.
As the race wore on the lead group was whittled down to six as Cameron, who has had an injury-interrupted season, attacked to create a decent lead on the climb prior to Kai Iwi.
She kept the pace on and extended her lead slightly heading up Goat Valley the last hill of the day with under 10km to travel.
The final loop of the race required the riders to carry on down State Highway 3 to the turn onto Blueskin Rd as Luff and Gemmell put in a big effort to drag the group back up to the tearaway leader.
They finally reeled Cameron in on a small rise on Blueskin, just before the turn to Western Station Rd.
With six riders in it for the sprint, Darcy Forrester launched early but was overhauled inside the last 200m which left Tucker and Cameron to fight tooth-and-nail right to the finish.
On the line it was Tucker, calling on his skills as a former top-flight junior track sprinter, who won by the width of a tyre from Cameron.
The hard-working Gemmell was a close-up third with a short gap to Luff , who got past Forrester in the dying stages to grab fourth.
Behind Forrester was Black who turned in a great effort for sixth. The rest arrived at short intervals thereafter, with Darby in eighth being first of the break bunch, while Goode burned off his co-markers on scratch to clock the day's fastest time 2.09.43.
Cameron's effort will be a good confidence booster ahead of the Oceania track championships, which kick off next week in Invercargill.
A field of 13 B-grade riders raced the 36km to Maxwell and return for the Paddy O'Brien Memorial Cup.
Limit riders Joseph Loveridge-Mills and Victoria Catetook full advantage of their handicap and finished first and second respectively. However, both were ineligible for the trophy as Loveridge-Mills is a junior and Cate an A-grade rider, tuning herself back up after an injury break.
Consequently it was Julie Weir, from further back in the handicap riding a great race for third, who claimed the cup.
Teenager Michaela Walker did well for fourth, with veteran Jim Callaghan battling on for fifth ahead of club stalwart Debbie Cain.
Fastest time went to scratch rider Carl Rusden (1.05.27).