Still active at national club championship level, McGrath started in a lead group of four riders and then peeled away by the third lap to run his own race.
"Good levels, really nice."
It was his first time competing in Wanganui and it won't be his last.
"Nice new roads, new course. I'll be back."
McGrath said he had hoped to pit himself against Gordon McCauley, the 2006 Commonwealth Games bronze medallist, who did not compete with illness.
Supporting his wife, who was racing, McCauley said McGrath was about 10 years too late.
"If we'd have raced, I'd have beat him as he doesn't have a sprint," McCauley laughed.
Other riders were not so fortunate. Taranaki's Wayne Gunderson was left with a nasty cut on his arm following a crash and also got into a heated debate with officials.