Sussex put in a great performance in their 50-over game with Australia, however they suffered a 57 run loss at the County Ground on Thursday evening.
The hosts won the toss, with skipper Ben Brown electing to field for the opening innings in Hove against the One Day World Champions.
Openers D'Arcy Short and Aaron Finch frustrated the Sharks for the first 10 overs, however Danny Briggs bowled the former out LBW during his first spell with ball in the 11th over with the score 74 for 1.
Finch put on a 93-run second wicket stand with Marcus Stoinis, however he was caught behind by Brown off the bowling of Jofra Archer, who ended the innings with three wickets
What followed was a mid-order collapse that saw the Aussies lose their next four wickets for 13 runs in a 31 ball spell just after the 30-over mark. Spin bowling from Briggs and Luke Wells helped break down the visitors during that period, with the duo both ending the game with two wickets.
All-rounder Stoinis weathered the storm as his teammates continued to fall around him, however he eventually fell for the eighth wicket in the 47th over, caught off the bowling of Archer by Laurie Evans. The 28-year old posted a total of 110 off 112 runs, hitting nine 4s and seven 6s.
Australia reached the end of their 50 overs on 277-9, setting the hosts a total of 278 to win.
It was a nervy start to Sussex's innings as they quickly lost opening batsman Luke Wells three overs in, with Phil Salt lucky not to be following him back to the dressing room after Short dropped two catches off the bowling of Michael Neser and Jhye Richardson.
Those drops proved costly for the visitors, as Salt went on to post a 33-ball 50, hitting five 4s and four 6s on the way to his half century. He was eventually bowled by Kane Richardson for 62 off 49 balls.
The 21-year old helped put the Sharks in a strong position with his 91-run stand alongside Evans, who also grinded out half a century off 58 balls before being bowled and stumped by Ashton Agar and Aussie skipper Tim Paine for wicket number seven.
With the target of 278 still realistically within reach heading into the final ten overs, there was hope that the Barbadian duo of Chris Jordan and Jofra Archer could guide the hosts to a famous victory over the visitors. However confusion between the pair saw Jordan ran out, with the latter bowled LBW by Andrew Tye in the following over.
Jhye Richardson cleanly bowled Abi Sakande's stumps to seal victory for the visitors with 45 balls to spare.
Sussex: Wells, Salt, H. Finch, Evans, Brown ©, Burgess, Wiese, Jordan, Archer, Sakande, Briggs
Australia: Short, A. Finch, Stoinis, Maxwell, Head, Paine ©, Agar, Neser, J. Richardson, Tye, K. Richardson