“It was a good effort and he did things pretty right,” Oulaghan said.
“It suits him down here, although he wasn’t flash at that one fence, which meant we had to work for it.
“The National has always been one of those key jumping races in New Zealand, so I’ve always been keen on winning it.
“We may possibly go to the Northern now but it depends on how he comes through this and we see what the weights are.”
The Great Northern Steeplechase (6400m) will be run at Te Rapa on September 17.
West Coast took his career record to seven wins from 28 starts, with all victories coming over fences.
Earlier on the card, second-season jumps jockey Portia Matthews produced a gem of a ride aboard Berry The Cash to capture the 133rd Grand National Hurdles (4200m).
The lightly raced 7-year-old son of Jakkalberry had caught the eye when finishing off strongly in the Sydenham Hurdles (3100m) on the first day of the meeting, with the additional 1100m of the National making him one of the favoured candidates for the contest.
Settled near last by Matthews as race favourite and first day winner Happy Star set a steady tempo in front, Berry The Cash bided his time before moving with 800m to run.
Happy Star had looked to break the field apart at that point, with stablemate Obrigado chasing hard as Berry The Cash loomed ominously into contention.
The Oulaghan runner joined Happy Star as the pair went head-to-head over the last two obstacles, with Berry The Cash finishing best to win by a widening five-length margin at the line.
Matthews was emotional as she paid tribute to Oulaghan for taking her on just over 12 months ago.
“This makes everything worth it in respect to how hard it has been to get here for me and the horse,” Matthews said.
“He is green and so am I, we have taken a while to work out our tactics, although I knew the extra ground would work out. Mark has been everything to get me to where I am.
“He [Berry The Cash] has always been my favourite, and when I first rode him, that is when I met Mark, so he is a very special horse to me.”
- Racing Desk