The recent cold spell of weather that swept across the UK left the track covered in snow just over a week ago with huge drifts accumulating by the famous fences.
However, Claisse refused to employ machinery to clear the course, fearing tyre tracks would churn up the ground, and instead had his team of around 60 staff shovelling the snow by hand.
And now he has had to contend with heavy rain on the course which has officially left the going “heavy, soft in places” with just over 24 hours to go until the first race on Tuesday.
“We’re okay, the track has taken the rain better than I anticipated,” Claisse said today.
“There isn’t much standing water around.
“We had a fairly intense period of rainfall between six and seven o’clock last night and again early doors this morning.
“Further rain is forecast through the day [three to four millimetres] so we’re not anticipating seeing much change.”
And while the overnight forecast is far from ideal, the clerk of 18 years at Cheltenham is confident conditions will improve.
“We’re expecting a dry night and a dry day tomorrow,” Claisse added.
“We’ve had a wet lead-up and have had 45/46 millimetres of rainfall in the last 10 days.
“That came on the back of a week when temperatures were as low as -6C on the ground and -17C in the air, so it’s been a challenging build-up.”
But some of the festival’s top trainers are less confident.
“I expected it to be a lot messier,” said Nicky Henderson while walking the track yesterday.
“Some of this is puddingy right here [just after the last fence].
“It’s the first bit you walk on to and it’s very nearly the worst bit.”
And Alan King reckons the latter part of the week could be very challenging indeed.
“Where the fresh ground is, it’s not too bad at all,” King said.
“But there’s not a huge amount of it.
“On the ground that’s been raced on through the winter, it’s showing signs of having taken a hammering.
“It’ll be testing.”