Slimmed down Clarke two shots off the lead in South Africa
Raphael Jacquelin claimed the clubhouse lead with a brilliant 67 at the Volvo Golf Champions with a slimmed-down Darren Clarke and Colin Montgomerie hot on his heels in Durban.
Jacquelin defied strong crosswinds blowing in from the Indian Ocean to be the only player in the elite 36-man field not to drop a shot, the Frenchman carding a five-under-par 67 that featured three birdies in the last five holes.
Playing partner Montgomerie, who has largely played seniors golf since turning 50 last year, finished in the same vein to reach two under, while Clarke went one better with a three-under 69.
Former Open champion Clarke has lost almost three stone in weight since October as he looks to reproduce the golf which brought him a first major title at Royal St George's in 2011.
The 45-year-old has failed to record a single top-10 finish on the European Tour in the last two seasons and said: "My objectives are getting back to playing some of the golf I know I can play. I have had a frustrating last couple of years where I have not played that badly but made stupid mistakes.
"I took a look at myself in October and thought I was getting too fat so it was time to do something about it. I spend a lot of time in the gym and changed my diet and hopefully I will reap the benefits.
"I plan to keep doing what I am doing and maybe get stronger and stronger. I hit a drive on the 10th today of 300 yards back into the wind and another driver from 280 yards to the green and I couldn't have done that before."
Montgomerie was inches away from winning a Volvo Backhoe Loader excavator worth 75,000 US dollars (£45,500) by making a hole-in-one on the par-three 15th, although he admitted he would have swiftly asked the tournament sponsors for the cash instead and split it with caddie Alistair McLean.
The former Ryder Cup captain added: "I was playing well at the end of last year and I started to play a lot more golf. I had not been having much fun on 7,500-yard courses on the main tour but I am a member of three tours now (European Tour and two seniors tours) and it's given me more freedom to choose courses I can get round.
"It's very difficult and tricky out there. The wind was coming off the sea and made every hole a crosswind. You have to be very careful, you can make a mess out there in a hurry."