Japan's Daiya Seto set a World Cup record of 4:00.12 to keep Hungarians Laszlo Cseh and David Verraszto at bay in the 400m medley on the opening day of finals at the Berlin round of the tour.

After stunning his rivals with a 54.87 butterfly opener, Seto set about his mission of keeping Cseh at bay on backstroke, the half-way lead split his 1:55.61 to 1:55.78. Seto settled the battle on breaststroke, turning into the last 100m on 303.08, Cseh on 3:04.37 on his way to second place in 4:01.42, Verraszto on 4:03.19 for third.

Seto was back later to take second in the 200m butterfly in 1:52.22. He went through the field from 5th to 4th to 3rd going into the last 50m, swept all aside on the way home barring the man at the helm, Nikolay Skvortsov (RUS), on 1:51.77. Tom Shields (USA) was pipped at the touch by Seto for third in 1:52.27.

The session started with another hand of experience falling shy of youth on the move. American juniors Rebecca Mann, 15, and Leah Smith, 17, stormed ahead of Lotte Friis (DEN) in the 800m freestyle. If all three were all but level with 100m to go, the end result was painful for the Dane: Mann, 8:16.58, Smith, 8:17.96, the 2009 world champion on 8:22.04.

Anthony Ervin (USA)  led from start to a 46.71 victory in the 100m freestyle, his half-way split of 22.03 half a second up on the chasing pack. Tommaso D'Orsogna (AUS) took second in 46.99, Darian Townsend (RSA) 0.03sec behind, Olympic-year perspective provided by the man in fourth, Yannick Agnel (FRA), on 47.04. That was the same finishing place Agnel endured at London 2012 in a week in which he became Olympic champion over 200m and brought France home to victory in the 4x100m freestyle.

His training partner, Olympic 400m free champion Camille Muffat brought her own perspective to the World Cup: if Katinka Hosszu (HUN) had dominated the 200m free on tour so far, Muffat's 1:52.28, 0.01sec inside her own French record, blasted her rivals into touch. Muffat's teammate Charlotte Bonnet took joint second with Hosszu in 1:55.14. The splits for Muffat, Olympic silver medallist over 200m, were a class apart: 26.32, 54.89, 1:23.68, 1:52.28.

If the result appeared to knock tour leaderboard queen Hosszu, who finished fourth in the 200m medley in 2:09.14, then Zsuzsanna Jakabos, fourth in the 200m free, celebrated a rare moment of getting the better of her teammate with a 2:08.54 effort in the medley, only to find that Britain's Sophie Allen got to the wall before her, in 2:07.52. Celina Li (USA) kept Hosszu off the podium in 2:08.95 - but perhaps not the money: Li may not take her cash prize because of NCAA eligibility rules, leaving the money to the next best... Hosszu.

Having confined herself to sprint freestyle so far on tour, Jessica Hardy (USA) stamped her authority on the 100m breaststroke with a 1:04.58, almost 2sec up on next best, Japan teammates Mio Motegi and Rie Kaneto, on 1:06.38 and 1:06.52,  Allen making the podium for the first on the day, in 1:06.97.

The USA celebrated again when Sean Mahoney dominated the 200m breaststroke from start to a 2:04.55 finish. He turned in 59.50 at the 100m mark, no others inside 1:01, and held on to his solid lead. Henrique Barbosa (BRA) took second in 2:06.20, Marco Koch (GER) third in 2:06.84.

Ilaria Bianchi (ITA) has not been a name to reckon with when it has come to threatening for places on big podiums but in Berlin today she clocked a lifetime best and Italian record of 56.86 for victory over 100m butterfly, Louise Hansson (SWE) and Inge Dekker (NED) next home in 57.55 and 57.65 respectively.

In other action, Stanislav Donets (RUS) claimed the 100m backstroke in 50.02 ahead of Robert Hurley (AUS), on 50.73, his teammate Ashley Delaney on 51.04; Paul Biedermann (GER) clocked 3:42.21 to win a relatively weak 400m free final, Austrian David Brandl next home in 3:45.28, Germany's Robin Backhaus third in 3:46.88; Britta Steffen gave the hosts another cheer with a 24.16 win in the freestyle dash ahead of Hardy, 24.43, and Dekker, 24.56; George Bovell (TRI) scored another win over Kenneth To (AUS), 51.20 to 51.53 in the 100m medley, Townsend third in 53.04; and Melissa Ingram (NZL) made a smart move down the penultimate lap of the 200m backstroke to inch past US junior Kylie Stewart and then hold the lead for a 2:04.28 to 2:04.70 win, Germany's Jenny Mensing third in 2:07.31, Hungarians Jakabos and Hosszu feeling the strain of a long tour a touch adrift in 4th and 5th.