"I thought it was a better test than he did at Badminton," Paget said of Promise's performance.
"He was more consistent the whole way through."
Paget, who won the British Open one-day title at Gatcombe Park last month on Lush, acknowledged there was fresh pressure on him.
"It's certainly a new kind of pressure for me, but you put pressure on yourself anyway. I'm here to win and I'll do whatever it takes to try to make it happen."
Nereo, the last horse into the arena, produced a consistent performance, which pleased Nicholson.
"This was a step up from his test at Badminton, which had moments of brilliance and some more erratic moments. Today he was consistently better all the way through" said Andrew.
The cross country test tonight, which has 31 fences, will be a challenge, but Nicholson is confident of Nereo's ability to handle it.
"Nereo's tackled all sorts of courses all over the world. He prefers a big, galloping track as he's got such a huge stride and he has to work quite hard across the undulations here, but I'm sure he'll cope with it, as he's done before."
Standings after the dressage:
Jock Paget and Clifton Promise (NZ) 36.7 1, Ingrid Klimke and FRH Butts Abraxxas (Germany) 39.0 2, Andrew Nicholson and Nereo (NZ) 41.3 3, William Fox-Pitt and Parklane Hawk (Britain) 41.5 4, Paget and Clifton Lush, and Andreas Dibowski and FRH Butts Leon (Germany) both 42 equal 5, Nicholson and Avebury 42.3 7.
Also: Jonelle Richards and The Deputy (NZ) 46.2 12, Nicholson and Calico Joe, and Mark Todd and Oloa (NZ) both 48.3 equal 18, Todd and Ravenstar 55.5 equal 41, Richards and Flintstar 58.2 equal 53.