Westminster School are still on course for the triple crown having beaten Hampton School in this afternoon's second round of the Princess Elizabeth Challenge Cup at Henley Royal Regatta.
They are already National Schools' and Schools' Head winners and are seeking to add the schoolboy event title here. They won by a length and a third during the post-lunch sessions in which the USA's huge entry began to make its presence felt.
No fewer than 23 American crews were in action as a precursor to the next two days' racing which will see some significant US rivalries on the Henley Reach.
For the first time in almost a century two American "giants' will go head-to-head at Henley 2015 when the Universities of Princeton and Washington race each other in the heats of the Ladies' Challenge Plate for intermediate eights.
Washington is the form crew, having won all heavyweight men's events in the recent US national college championships (the IRAs). Cox Stuart Sim said that his crew relishes the increased expectation that comes from being the champions: "We've always got a target on our back; other people are going to be disappointed after their results at IRAs and this is their chance at redemption".
Perhaps these two US crews could be forgiven for secretly cursing the vagaries of the draw in the same way that today saw two Japanese crews travel across the World only to race each other in the Silver Goblets for men's pairs.
Sumito Nakamura and Noritaka Kamada won and will now race Calum McBrierty and Mat Tarrant from the GB squad. "We've all just graduated from the same university back home so we had to win that one!" said Kamada.
In the opposing half of the Princess Elizabeth Challenge Cup draw to Westminster School, Boston College High School from the USA caught the eye, in freshening breezes, as they beat the selected Shawnigan Lake School from Canada.
Earlier in the day, when conditions were calmer on the water, there were several close races before the breeze picked up.
European lightweight single finalist Zak Lee Green was in the Imperial College and Agecroft Prince of Wales quad that were pushed all the way by some "oldies but goldies" from Molesey B.C. and Sir William Borlase's Grammar including 2013 World men's eight Champion Dan Ritchie and Olympian Tom Solesbury.
Lee-Green who earned his GB senior colours last season whilst also studying for his dentistry finals said of his crew's three-quarter length win in this intermediate event: "We're happy with the win but there is a lot we can learn from it as well".
Tyne A.R.C. and N.R.C. Oslo from Norway were involved in a tight tussle in the Wyfold Challenge Cup for club fours. The Tyne crew were down by three-quarters of a length at the three-quarter mile mark but came through to win by just a third of a length.
An Antipodean battle in the same event saw the New Zealanders from Petone R.C. pull back a big, early deficit against Sydney R.C. to come through and win by a length.
Tomorrow will see top international crews joining the fray in bigger numbers. The programme will include a first look at European men's pair Champions James Foad and Matt Langridge in the Silver Goblets and Nickalls' Challenge Cup.
Foad picked up a wrist injury and the duo sat out the world cup in Varese 10 days ago.
The GB women's eight will also be in action, racing here as Leander and Imperial College. They sent a buzz around the world at the last world cup when they led the American Olympic Champions in the heats with a head-turning first-half pace. Tomorrow they take on Leander Club in the opening round.
Their main rivals here should be the Canadians who are the World Silver medallists and the two crews, if successful tomorrow and Friday, would face each other in Sunday's final. "It would be good to have another crack at them", said Zoe de Toledo, the GB Rowing Team cox.
Seb Devereux, meanwhile, a world junior finalist two years ago, will have one of the biggest races of his life tomorrow. The 20 year-old's single scull heat win this morning puts him through to meet Olympic Champion Mahe Drysdale of New Zealand.
Drysdale, like Mirka Knapkova of the Czech Republic in the equivalent women's event, is seeking a fifth Diamond Challenge Cup win here this year.
Racing starts at 08.30 BST and runs until 17.20 with an expected 67-race programme including many quarter-finals.
Henley Royal Regatta has adjusted its schedule tomorrow to delay the planned 12 noon race so that rowers, spectators and all other Regatta personnel can observe the nationwide minute's silence called by the Prime Minister in respect of those who lost their lives in the recent events in Tunisia.
A further thrilling aerial display from the RAF is planned after today's appearance by the world-famous Red Arrows.