Both are New Zealand mountain running representatives and often train together, so Coubrough sought Thorburn's advice on how to approach his first assault on New Zealand's premier multisport event.
"Dougal has been an inspiration for me," he said.
This inspiration paid dividends for Coubrough on his way to victory.
He carried a 25min lead into the second day of competition, beginning with a 15km bike from Klondyke Corner to the start of an extremely testing 67km kayaking stage down the Waimakariri River, in gusty conditions.
His goal was to hold out all the two-person competitors, both in the initial bike and in the kayak, and then just hold on over the 70km bike ride from Gorge Bridge to Sumner beach.
"I had one team guy fly past me on the bike but, yeah, it was a bit lonely out there. It all worked out OK in the end."
Coubrough finished in 11hr 25min 2sec, well clear of second-placed Dan Moore (Picton) in 11hr 51min 46sec and Scott Hawker (Christchurch) third in 12hr 31min 21sec.
The 29-year-old self-employed builder has no plans for racing of any sort in the immediate future, but will contest the New Zealand mountain running championships in April.
"I guess that's the next thing to aim for. I haven't won a New Zealand title, so I'll try and win that if I can."
Coubrough is unsure if he will be in contention for the New Zealand team, however, given a recent run of illnesses and injury, but he is keen to make the Commonwealth mountain running team for Wales in September.
Like Coubrough, Canterbury's Hayley Shearer made the most of her overnight lead of 12min 45sec to hold out Olivia Faull (Christchurch) and Louise Hales (Wellington) in the women's two-day race.
The three overcame a high river level and strong wind gusts on the kayak stage that saw many others falter.
Shearer recorded 13hr 53min 13sec, finishing 7min 11sec clear of Faull, with Hales clocking 14hr 21min 37sec.
Luke Vaughan (Christchurch) and Peter O'Sullivan (Palmerston North) proved an unstoppable combination, lifting the two-day team crown for a second consecutive year, in 11hr 8min 18sec.
Vaughan, the 2005 individual two-day champion, and fourth in the Longest Day in 2009, is originally from Mosgiel, and has family and friends still living in the area.
Scott Wilder (Christchurch) and Matthew Blundell (Australia) came through on day two to clinch second place in 11hr 13min 26sec, while the dental duo of Steve McKinstry (Auckland) and Joseph Petelo (Dunedin) finished third in 12hr 2min 18sec.
Ashburton school teacher Claire van Polanen teamed up with New Zealand canoe polo representative Olivia Spencer-Bower to win the women's team section in 12hr 46min 58sec.
