By John Kenny in London
The start of the swimming events in London on Saturday morning could not have thrown up a more exciting race than the men’s 400 metres individual medley (IM).
The big two Americans Michael Phelps and Ryan Lochte go head-to-head in the first gold medal event at the London Aquatic Centre.
Lochte, the reigning world champion, who is bidding for six gold medals in London, beat Phelps in the US trials and says he has never been in better shape.
He is a genuine threat to Phelps, the Baltimore Bullet, who has a staggering 14 gold medals to his name, including a record eight from Beijing four years ago.
Phelps climbed from the pool in China four years ago and said "never again" about the demanding 400m IM. A race that includes all four strokes: butterfly, breaststroke, backstroke and front crawl - better known as freestyle.
But he is back in what he says is his last Olympics as he bids to better Larisa Latynina’s Olympic medal haul. The Soviet Union gymnast has 18 Olympics medals to her name; Phelps has 16, including two bronze.
The duel between Lochte and Phelps in the 400m IM on the opening night will set up the eight days of competition beautifully, while the pair will meet again in the 200m IM.
Lochte's other events include the 200m backstroke, the 200m freestyle and the relays.
Phelps is competing in seven events this time around having pulled out of the 200m freestyle, despite having qualified for the discipline at the US trials.
TEAM IRELAND IN THE POOL
Barry Murphy will be Ireland’s sole representative on the opening day as he goes in his favoured event, the men’s 100m breaststroke, where he is the Irish record holder in 1 minute 00.77 seconds, his Olympic qualifying A time.
Murphy, now 26, missed out on Beijing and was bitterly disappointed not to be considered for selection four years ago. He was a very angry young man.
But the years have softened the Dubliner, and the switch to Michigan, where he is now trained by US-breaststroke specialist Mike Bottom, has done the trick.
He was the first swimmer in the world to qualify for London, making the qualifying time two days after the Olympic cycle date opened.
Murphy is in lane eight of heat four on Saturday morning, bidding to make the top-16 times and secure a place in that evening’s semi-final.
It’s a tall order, but maybe the time has finally come for the new chilled-out Irishman.
Grainne Murphy withdrew from the women’s 400m IM heats and will first see action on Sunday in the 400m freestyle, along with Ireland’s two other competitors: Melanie Nocher (100m backstroke) and 17-year-old Sycerika McMahon (100m breaststroke).
Other highlights from day one will be the women’s 100m butterfly, where American Dana Vollmer is bidding for the first women’s US gold since Amy Van Dyken's win back in 1996 in Atlanta.
As well as the women’s 4x100m freestyle relay were the US will try and unseat the Netherlands, who are the reigning champions.
Nick O'Hare, the 1996 Irish Olympian, and I are here to bring you TV commentary on all the finals and many of the heats, while I will also be commentating on the diving which takes place at the impressive Aquatic Centre in between the swimming sessions.
Swiming dominates week one before the athletics take over.
Let the games begin.
John Kenny is an RTÉ Sport journalist and broadcaster.