(CNN) -- Luke Donald demands perfection of himself and his caddy on the golf course, so when CNN presenter Shane O'Donoghue was given the chance to carry the world No. 1's bag for a few holes, he knew the learning curve would be steep.
Donald reached the top of the rankings earlier this year by winning the PGA Championship at Wentworth -- despite the best efforts of O'Donoghue to derail his effort in a practice round for the European Tour's prestige event.
Donald's regular caddy John McClaren was on hand to give some useful tips, but it appeared wasted on the Living Golf host.
Donning a fetching pair of shorts and the obligatory caddy's bib, O'Donoghue hardly made the best impression on their first hole, the 15th at Wentworth, when he marched down the fairway without a key item.
"You will need the clubs, that's the first thing!" said McClaren, Donald's caddy since the Englishman parted company with his brother Christian, who had previously carried his bag throughout his professional career.
"It was affecting our relationship," Donald told O'Donoghue. "I'd rather have him as a brother than a caddy."
Under McClaren, Donald has flourished, rediscovering the form that had taken him into the top 10 after victory in the 2006 Honda Classic and becoming a regular in the European Ryder Cup team.
Victory at the 2011 Accenture WGC World Match Play Championship in February put him on the brink of the No. 1 spot going into May's Wentworth event.
Despite his easy-going reputation, Donald's patience was clearly tested again by the enthusiastic if not exact O'Donoghue -- who next managed to leave behind another piece of golf apparel, the towel to wipe the clubs.
His yardage advice also fell short of expectations when Donald hit an approach into a bunker, but saved his par with a superb up and down from the sand.
A relieved O'Donoghue thanked his "boss" for saving his bacon as he showed just why he was about to take over from Lee Westwood at the top of the rankings -- his superb recovery play.
Donald said he had made the big mistake of thinking "I needed to hit it further" to get to number one, and that it affected his swing and his form.
"It has taken me three or three years to get back to my best," he added.
But a rare error off the tee at the par-five 18th at Wentworth left Donald in the trees until he brilliantly engineered another miraculous recovery.
Turning to O'Donoghue for club selection, he looked a little surprised when the Irishman pulled out a three-wood and encouraged him to have a tilt at the water-protected green.
Despite a good connection, the ball found a watery grave.
"You should have told me to lay up short," was Donald's assessment.
"He's one of the best players in the world at getting up and down from off the green," chipped in McClaren. "He would have salvaged par."
Suitably chastened, O'Donoghue's first tilt as a "professional" caddy had ended in the golfing equivalent of a red card!
Fortunately, McClaren had taken back the bag a few days later when Donald beat Westwood in a playoff to win the PGA Championship and become world number one for the first time.
By then O'Donoghue was back to doing what he does best, presenting Living Golf.