NEW Zealander Andrew Nicholson has put himself firmly on course to post the glaring missing entry in his stellar career portfolio by taking early charge of this year's Mitsubishi Motors Badminton Horse Trials.

Wiltshire-based Nicholson has completed Badminton's demanding dressage, cross-country and showjumping programme a record 33 times - but he has yet to win it.

It is an anomaly during an eventing career highlighted by five Olympic and world championship team medals, plus one world individual, five Burghley triumphs and other four-star victories at Kentucky, Pau and Luhmuhlen.

But Badminton has always eluded the 53-year-old, with him filling every top-five place at world eventing's most prestigious competition - except first.

That could change this year, though, following a dressage score of 37.8 penalties that secured a commanding overnight advantage from his fellow New Zealander and 2013 Badminton champion Jonathan Paget on Clifton Promise.

Germany's Niklas Bschorer, at 20, the youngest competitor among an 81-strong Badminton field, lies third aboard Tom Tom Go 3, with 27-year-old Flora Harris currently the leading British challenger in fourth with Amazing VIII.

Several of Nicholson's major challengers will enter the dressage arena on Friday - the likes of British pair William Fox-Pitt and Oliver Townend, plus German star Ingrid Klimke - while six-time Olympian Nicholson has a second ride on Calico Joe, but he has delivered an early warning signal to all his title rivals.

"From start to finish, it was the smoothest test he has done," said Nicholson, who made his Badminton debut in 1984.

"It felt as though it all just flowed a bit smoother than at other times, and it was good to see that the judges thought the same.

"It is a major thing to come to these places on a horse I have been riding for so long. He is a horse that likes to work.

"I know him very well, and I know he will give me 100 per cent in the arena. He is very focused on what he does, and I get a great feeling of achievement to come out with a result like this one today."

Assessing Saturday's cross-country course, Nicholson added: "I think it is very fair. I don't think there are any surprises for the horses. You have just to ride it accordingly.

"I was very pleased with the course last year. He (course designer Guiseppe della Chiesa) hasn't shied off from last year. For sure, there is enough to jump out there."

Paget, meanwhile, marked his Badminton return with a stylish performance after being unable to defend the title last year due to a lengthy suspension imposed after Clifton Promise tested positive for the banned substance reserpine.

Paget, though, consistently protested innocence, and he was cleared in August last year, opening the door for him to resume his competitive career.

And the combination did not disappoint in early morning blustery conditions under grey skies, scoring 41.2 to stand 0.9 penalties ahead of Bschorer, while four-time Badminton champion Mark Todd completed a successful opening day for the New Zealanders by holding fifth spot with Leonidas II.

"I was very happy with him," Paget said, of Promise's performance. "He's such a professional now, and he went in there and did his job for me. I thought it was a really good test."

And looking ahead to the cross-country phase, Paget added: "I've walked the course once, and I really liked it.

"I think it is big, as it should be. The questions are fair. If you ride it right, the horses will understand the questions.

"This is four-star, and you have to get it all right, otherwise you get punished."

For Bschorer, it was a Badminton debut to savour as he went from spectator last year to top three on the opening day, and his preparations for Saturday when he walks the course will be assisted by Todd and Germany's national team trainer, Yorkshireman Chris Bartle.

"The atmosphere here is quite unique, very special. It was a brilliant test," Bschorer said.

"I think the course is do-able, so I am looking forward to Saturday. My horse has loads of scope."