Ben Hutchinson overcame a flu bug to claim three records and four titles at the Sussex Championships.
He won the boys' and men's 50m and 100m backstroke at Crawley and beat two records set by Simon Burtenshaw (Shiverers) in the junior events, clocking 28.04sec and 1min.00.77sec.
Ben's other record was in the senior 50m (28.04) when he beat the time set by Richard Salt (Shiverers) two years ago.
Illness forced him out of the Wycombe Open a week earlier.
This made it more important for him to do well at Crawley, with the senior national championships and a schools international for England on his schedule next month.
Ben, a pupil at Imberhorne (East Grinstead), said: "I have been cutting down anway on competition because of my GCSEs in the summer.
"Illness gave me even less opportunity to warm-up for next month so I was pleased to find some form.
"If you had told me I would be competing, let alone winning and breaking records last week, I wouldn't have believed you.
"It worked out well, although I am still a little bunged up. I certainly did better than I thought I would."
Ben's twin Chris was runner-up to his brother in all four events.
Ben, already 5ft 11in after a growth spurt, said: "I seem to have the edge on Chris at the moment."
The Crawley club swimmer added with a smile: "I work harder than him so I deserve to."
Ben, will miss the second of five County Championship meets at Crawley on Saturday to rest and study.
He joked: "I'll give Chris a chance to win something this weekend."
Brighton club ace Holly White came through to win the 14-year-old girls' 100m butterfly. The Patcham pupil triumphed in 1min.07.24sec.
Organiser Brian Smith said: "Holly put in a great effort because she was laid up for two weeks with the flu and was not fully fit.
"But she clocked the fastest butterfly time of the day.
"It was three seconds faster than any other swimmer and that included Cheryl Miller, from Bognor, who won the next age group."
Mark Harrington (Crawley) recovered sufficently from flu to secure second place in the boys' 400m freestyle and was third in the open event.
Emma Eaves (Brighton), also suffering with a bug, was second to clubmate Hannah Belameh in the 12-year-old girls' 100m breaststroke.
About 15 potential medal winners had to miss the championships due to illness, including international Claire Manton, from Brighton and Hove.
Smith said: "The bug is sweeping through clubs and schools so there were unexpected results because some competitors were either not fully fit or not there.
"But it was still a good quality meet with lots of decent swims and around 250 competitors."
Brighton Dolphin, based with Brighton at the Prince Regent pool, produced their first county champions.
Emma Harding secured the nine-year-old girls' 200m freestyle and clubmate James Hart the ten-year-old boys' 50m breaststroke.
Dolphin spokeperson Tyrone Dowd said: "It is fantastic. We've waited 20 years for our first county champion and then two come along at once, just like London buses!
"We are only a small club so this is a great achievement. It is all down to the hard work the swimmers put in."
Hastings also had two wins throigh James Lawton (15-year-old boys' 100m breaststroke) and Frankie Wall (nine-year-olds boys' 200m backstroke).
Crawley posted a warning to Brighton, who are rated the leading club in Sussex.
They scored ten victories overall, one more than Brighton.
Smith said: "Brighton have had the edge for three years but Crawley have always been strong in that time."
St Bede's (Upper Dicker) scored six victories and Bognor four.
East Grinstead managed a one-two-three in the ten-year-old boys' 200m backstroke with Richard Thorne first, followed by Thomas Lamb and Matthew Ruxton.
Clubs with one win included Smith's Squad (Eastbourne), Shiverers, Eastbourne, Worthing, East Grinstead, Burgess Hill, Hailsham, Haywards Heath and Beacon (Crowborough).
Other competing clubs were Atlantis (Horsham), Littlehampton, Cottesmore School (Crawley), Chichester, 1066 (Hastings), Bexhill and Lewes.
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