For Long, leader after each of the first two rounds, it proved to be a tough day both mentally and physically as international representative Tang and 52-year-old Collins made him dig deep into his reserves of skill and stamina.

''I've not been in a situation like that since my college days eight years ago,'' said San Diego-born Long, who arrived in Hong Kong last May.

Leading by one from Tang and three from Collins at the start of the day, there was little indication of the dramas that lay ahead as Long parred each of the opening nine holes to maintain his advantage.

However, any thoughts of a Sunday stroll were dispelled from Long's mind at the par-five 10th where his pitch from 40 yards landed on the green and rolled into the water.

A double-bogey seven resulted and when he dropped a stroke at the 11th it enabled Collins, winner of the 36-hole senior championship held concurrently with the main event, to draw level.

When Collins made a birdie at the par-five 14th he went ahead for the first time in the Shell-sponsored tournament and appeared capable of becoming the first man to win both the senior and amateur championship.

Collins retained the lead until a bogey at the 17th. He completed his morning round in 73 and went into lunch tied on 217 with Long and Tang who was round in 75.

In the afternoon, Tang dropped off the pace with a double-bogey six at the first and Long regained the initiative with a 12-foot birdie putt at the short second.

With seven holes remaining the difference between Long and Collins was still one. It was at the par-four 12th, following a break for drinks, that the decisive twist took place.

Collins played his one bad shot with his ball coming to rest against the fence on the left side of the fairway. He finished with a triple-bogey seven to Long's four.

When Long produced an exquisite chip to ensure a birdie at the 14th and extend his lead to five, the contest was over.