Sederholm, 24, is trained by her Swedish-born father, Lars, who was also responsible for the United States Olympic team. Having made 72 trips across the Atlantic in the last three years, Lars has now relinquished the American connection and will concentrate exclusively on his training establishment at Waterstock House in Oxfordshire, where Tina is an instructor.
'My philosophy and training come from Dad, I have absolute faith in his judgement,' Sederholm said yesterday. She now holds a narrow 0.2pt advantage over Australia's Felicity Cribb on Carmody Street and Britain's Lucy Thompson on Crackshot.
The order could well change today when New Zealand's world champion, Blyth Tait, rides his dressage test on Ricochet. Tait's partner travelled to Barcelona as his reserve Olympic horse, which is the reason why he is now competing at Blenheim rather than facing the stiffer challenge of Burghley next weekend.
'It would have been unfair to give Ricochet only a week's holiday and then try to regain the level of fitness you need for Burghley,' Tait said.
The New Zealander's presence was not bothering Sederholm as she held the overnight lead. 'There are some brilliant riders here and you could easily be overawed by them, I just think of the competition as a challenge for myself,' Sederholm said.
Mike Etherington-Smith's 29 cross-country fences, which riders will tackle tomorrow, are regarded as more difficult than in the previous two years. 'Mike adds a new dimension each time, giving us more to think about,' Tait said.
BLENHEIM AUDI HORSE TRIALS (Standings after first day of dressage): 1 Chinook II (T Sederholm, GB) 51.2 penalties; 2 Carmody Street (F Cribb, Aus) 51.4; 3 Crackshot (L Thompson, GB) 53.6; Shannon (K Lende, US) 54.6; 5 The Hologram (R Dumas, Fr) 54.8; 6 Kilbernie (G Law, GB) 55.0.