Elite winner Dirk Peters was happy just to complete what he describes as New Zealand's best-known event in 1hr 47min 53sec, before finding out he had broken the record.
The Glendhu Bay to Arrowtown race attracted 2000 riders this year, a cap organisers had put on the event.
Peters beat hot favourite Brad Hudson, who clocked 1hr 48min 8sec, and was surprised to have set a course record.
''I thought I had just missed it,'' Peters said.
This was Peters' first time competing in the event and he was impressed with the terrain and scenery of the off-road course, which runs through the Motatapu, Glendhu and Soho stations.
''It was pretty hard, yeah. It's a big event, a massive event and probably the biggest participation rate of any in New Zealand.
''It's my first time down here and I loved it.''
Peters said the river crossings of the last 10km as the course ascends into Arrowtown were the biggest challenge and he never felt at ease with four riders hot on his tail the entire race.
''Brad and I were battling it out and then I could see I was running out of hills, so I thought I better speed up.''
Kate Fluker comfortably won the elite women's section with her time of 2hr 9min 35sec.
The 42.2km off-road marathon brought in two first-time competitors and winners of the event in Chris Dunell (26), of Christchurch, and Marjolein Ros-Cook (28), of Wellington.
Dunell, a policeman, said he was lucky to have been given the day off to compete and was surprised to win the event in 3hr 5min as it was only his second marathon.
''I'm pretty happy they gave me the day off today,'' he said.
''I love this place. It was absolutely stunning. I don't think I'd run on road again.''
Dunell stopped three times throughout the race to ''sort out'' cramp in his legs.
''It was tough out there.
''I was running solid for most of the race and it was a complete mind battle, really.''
His tactic was to break the race down into quarters and get through to each station before battling through the crossings in the Arrow River, where he thought he had run out of steam.
Dunell said he and second-placed Struan Webb (23), of Feilding, ran with each other for 3km and discovered they had mutual friends.
''It's a small world here in little old New Zealand.''
First-time Motatapu competitor Ros-Cook, who finished in 3hr 33min 32sec, was impressed with the course and said the event was just a good excuse to see the Central Otago region.
''I got married in January, but I always run. I started ramping up the training in January.''
Race director Geoff Matthews said the event, in its ninth year, had been ''one of the best'' and he predicted a sellout for the 2014 10-year celebrations.
Other winners were: Miners Trail open men, Gary Melhuish (1.21.09); Miners Trail open women, Melissa Clarke (1.35.43); off-road triathlon pro men, Braden Currie (3.50.12); off-road triathlon pro women, Nicky Samuels (4.21.15); off-road team tri men, Pilates Steel (4.32.24); off-road team tri women, Just For Fun (4.49.04); multisport open men, Angus Watson (5.09.24); multisport open women, Renee Wilson (6.55.15).
