The American had taken the lead from Henderson after three- quarters of a mile and was allowed by the umpire to come across the course to scull ahead of the Leander man, sending the wash from each stroke into Henderson's path.
Henderson survived two minor shipwrecks in the last 200 metres, which must have damaged his rhythm when he was already at the extremity of his endurance.
He put in a fierce sprint which broke the American and brought him his first Diamond final. On the first day Henderson had said: 'This is my year.' At 31 he does not have many more to come and neither does his opponent today, Paul Reedy, also 31, who rows for Melbourne University.
Henderson is tall and finely built while Reedy is shorter and more powerful in the shoulders. Henderson, who trains on the Henley course for his club, will know best how to exploit the vagaries of the stream on the Berkshire station.
Earlier in the Grand Challenge Cup the University of London beat the National Lightweight eight by two thirds of a length as the heavy flow of storm water began to take effect.
London went almost three-quarters of a length ahead at the start, as befitted a heavyweight crew. As the crews on the course, which is straight but set in a curving river, reached the middle of the stream, the lightweights clawed back some of the margin and held on well through the middle of the race.
However at the end, where the course once more took the crews out of the worst of the stream, London were able to forge ahead to take the race by two thirds of a length.Reuse content