"We had the track setting up beautifully to start the day a dead4 but we got 17ml of rain in an hour late afternoon [yesterday] and now I think the best we can hope for is a slow7 and that is if it doesn't rain too much overnight.
"With the moisture already in the track, I can't see it coming back to a dead, I think it will slow all day," says the man who knows the Ellerslie surface best.
The Derby is usually at the limit of most 3-year-olds' stamina range, but on a slow track, there is the added concern of first handling the surface and then staying what might feel more like 2600m than the actual 2400m.
That makes the race a mystery, especially for the three favourites — Rocket Spade, Montre Moi and Tokorangi.
Rocket Spade has no wet form but his dam won on heavy in distance races; Montre Moi has won on heavy but the extra stamina test of a Derby on a slow track might be a test and Tokorangi has no wet form.
"I think our fella will love the wet and will be the last one off the bridle," said a confident Johno Benner, co-trainer of Montre Moi in at least one positive push.
The horses long-shot punters could gravitate to include Jason Belltree (heavy track win), Perfect Scenario and Lord Ardmore (both slow track wins) and Frontman, who hasn't raced on slow but whose trainers wanted cut in the ground for him.
It is an extremely inexact science though and the best each-way bet may be Perfect Scenario, who has been racing a touch one-paced but has the wet form and the country's best trainer and jockey.
But the untapped Frontman is a brother to Bonneval, who won an ATC Oaks on a bog track, and is trained by the Derby supremos Murray Baker and Andrew Forsman and has premiership-dominating jockey Danielle Johnson on board for the big race.
In the support races, it will be crucial for multi punters that $1.40 chance Amarelinha handles a slow surface in the Sunline Vase.
Amarelinha looked unbeatable on top of the ground but the race may have evened out now.
The Kings Plate becomes an interesting test, as many of the favourites are untried in serious races on a slow surface.
But the big guns in the Mufhasa Stakes — Need I Say More and Babylon Berlin — are two who do have serious slow ground performances to back them up.
Later in the programme, wide draws could become good draws as this Derby Day continues to throw up new tests.
Derby Day
What: One of New Zealand racing's iconic days.
When: Today, first race 12.15pm, the Derby at 5.04pm.
Where: Ellerslie Racecourse.
Can I go? Not unless you are an owner with a horse racing today or member of the club; both groups had to register with the club.
Track: Rated a slow 7 last night.