Round two at Rotorua was another mixed day for the Honda racer.
''I had a second and a first but then I had a bad start in the last race. It was hard to pass and I finished fourth.''
Mangakino-based Lamont (Yamaha) led the title chase at the mid-point by nine points from Gibbs with Cooper a further five points adrift. A sixth consecutive national title was still a possibility.
''Then I had two really bad races at Hawke's Bay. I crashed twice in race one and then got a bad start in race two, had to take my goggles off on the first lap and I finished ninth.''
Cooper bounced back to win race three at Hawke's Bay and went to the Taupo final in third place, 18 points behind Gibbs and trailing Lamont by 12.
Taupo produced a 2-1-1 scorecard and pushed Cooper back into second spot while Gibbs clinched the title and Lamont's effort ended with a crash in the final race.
''In the first race I was leading but I was taking the wrong line in one corner and Gibbs passed me. Overall it was good final round but in the end I was too far behind in the points,'' said Cooper.
Cooper revealed on Saturday that he'd been racing injured in the last two rounds.
''I've cracked a metacarpal on my right hand,'' he said.
''I wasn't even on a motocross bike. I was doing interval training on my road bike [bicycle] and I came off when the chain broke.
''It's been an annoyance on some of the bumps rather than a big problem.''
Cooper will spend time training off the bike in coming weeks as he prepares for the 12-round Lucas Oil AMA Pro Motocross Championship in the US.
He is travelling with mechanic Lee McLean in a privateer effort against the big US teams that starts at Sacramento, California on May 19.
''We've got a motorhome and we'll drive across the country to all the races,'' said Cooper.
''The plan is to enjoy the racing and do as well as I can. I should have good bikes and good suspension and I think we can do okay over there.''
Bay of Plenty riders featured in the standings across all classes of the MX Nationals.
Mt Maunganui's Rhys Carter (Kawasaki) finished the season fourth overall in the MX1 class and one place ahead of Rotorua's John Phillips (Honda).
Taupo's Brad Groombridge (Suzuki) claimed runner-up honours in a MX2 title that was dominated by Takaka's Hamish Harwood with 11 wins from 12 races while Te Puke's Logan Blackburn (Kawasaki) achieved sixth.
In the 125cc 2-stroke class Rotorua's Joshua Bourke-Palmer (Yamaha) was fourth overall.