The Swiss rider defeated Otto Becker, of Germany, on Herrmann's Bellenuit by just 0.09sec, with a little-known Swiss rider, Urs Fah, third on Jeremia.
Sixteen horses had jumped clear in the opening round, among them four for Britain: Everest Showtime (Nick Skelton); Midnight Madness (Michael Whitaker); Abbervail Dream (Di Lampard); and Comex (William Funnell).
But only Lampard achieved a second clear round to finish in fifth place, proving her superb eight-year-old partner is back to his best.
It was a morale-boosting performance for the rest of the show and for next week's Nations Cup meeting in Rotterdam, where Lampard will be in the British squad.
Michael Whitaker was narrowly defeated (by 0.18sec) when he rode Tuesday's winner, Everest My Mesieur, in the earlier Kerrygold International. This accumulator contest gave Ireland their first winner of the meeting, Captain John Ledingham on Garraun.