The overall record belonging to top New Zealand runner Phil Costley was considered a little unrealistic to surpass by Saturday's field.
Instead the lead three played the man, not the stopwatch.
"It was all fun and games until the last 2km," said Webb.
"I enjoy the hard work from about 30km onwards."
He had previously entered the half marathon section a couple of years ago and was delighted with his best ever time for a full marathon.
Webb hopes to break three hours at the Motatapu Off Road Marathon in March.
Jacobs acknowledged Webb "ran damn well", as the pressure went on from the bottom bridge.
"I think we were all playing possum, running together.
"It was a matter of hanging in there until someone blew."
Normally a 60km competitor rather than 40, Jacobs said he enjoyed the variances of the Wanganui run, which chops and changes from grass to gravel, while creating tricky turnarounds on the bridges which disrupts the running rhythm.
Also pleased was women's winner Maria Kroonenberg.
In her 14th marathon the Wesley runner gave the thumbs up for her first time competing in Wanganui.
"It's a beautiful course, I actually smiled around the entire time.
"They're lovely walkers, they all move out of the way, unlike bloody Aucklanders."
In contrast to the men, Kroonenberg did not have her grade competitors nearby so ran a "very internal" race.
Her time of three hours, 14 minutes was about five minutes below her best and only adds more determination to return next year.
Morrison said overall 709 competitors across the walking and running grades a race record with over 200 entries alone in the popular half marathon category.
Results
Marathon, Men: Struan Webb (Feilding) 3.03.51, 1; Curly Jacobs (Eltham) 2; Tim Carroll (Palmerston North) 3.
Marathon, Women: Maria Kroonenberg (Auckland) 3.14.34, 1; Nelda Hazelhurst (Wanganui) 2; Catherine Quin (Wellington) 3.
Marathon, Men's Walk: Joff Hulbert (Taradale) 4.48.31, 1; Tim Eaton (Wanganui) 2; Malcolm Gray (Auckland) 3.
Marathon, Women's Walk: Averil Sheehan (Palmerston North) 5.21.29, 1; Chris Maxwell (Tauranga); Helen Tobin (Napier) 3.
Half Marathon, Men: Brian Garmonsway (Lower Hutt) 1.15.00, 1; Jon-Paul Heather (New Plymouth) 2; Josh Payne (Wanganui) 3.
Half Marathon, Women: Wendy Cottrell-Teahan (Feilding) 1.31.41, 1; Sheree McLean (Palmerston North) 2; Michelle Walters (New Plymouth) 3.
Half Marathon, Men's Walk: Peter Zwart (Palmerston North) 2.09.54, 1; Colin Horne (Levin) 2; David Cushing (Palmerston North) 3.
Half Marathon, Women's Walk: Gai Marie Smart (Wanganui) 2.12.25, 1; Sue Robertson (Wanganui) 2; Sharon Wright (Palmerston North) 3.
10km, Men: Brad Mathas (Wanganui) 34.28, 1; Tom Ditchfield (Wanganui) 2; Rob Dabb (Palmerston North) 3.
10km, Women: Amie Simpson (Wanganui) 48.52, 1; Toni Johnston (Palmerston North) 2; Abi Wightman (Wanganui) 3.
10km, Men's Walk: Owen Rogers (Palmerston North) 1.10.43, 1; Malcolm Hutchins (Wanganui) 2; David McDonald (Wanganui) 3.
10km, Women's Walk: Tina Bell (Wanganui) 1.02.38, 1; Megan Allan (Wanganui) 2; Frances McLennan (Wanganui) 3.
5km, Men: Robbie O'Brien (Wanganui) 20.32, 1; Tarron McGinnis (Wanganui) 2; Peter Caldwell (Wanganui) 3.
5km, Women: Louisa Webber (New Plymouth) 27.03, 1; Zoe Bell (Palmerston North) 2; Emma Haitana (Ohakune) 3.
5km, Men's Walk: Jon Roskvist (Upper Hutt) 31.14, 1; Arthur Stokes (Wanganui) 2; Rudolf Kemp (Wanganui) 3.
5km, Women's Walk: Donna Jackson (Wanganui) 38.14, 1; Cheryl Hood (Wanganui) 2; Chloe Hood (Wanganui) 3.
3/4 Marathon Run: Martin Minee (Palmerston North) 2.24.52, 1.
3/4 Marathon Walk: Rob Weir (Palmerston North) 3.44.40, 2.
