Zimbabwean Sean Ervine hit 20 four and four sixes in his 167 off 140 balls
Hampshire piled on the runs at the Rose Bowl to keep FP Trophy hopes alive with a 77-run win over Ireland.
Sean Ervine hit his one-day best 167no as he and Michael Carberry (121no) broke the county's third-wicket limited-over record in a stand of 260.
The Irish responded gamely to Hampshire's 316-2, new Notts signing Kevin O'Brien making 94 out of 239-9.
But they never recovered from Dominic Cork's new-ball burst, the former England all-rounder taking 4-20.
Cork rolled back the years with a seven-over burst in which he took the first four wickets, finding pace and bounce in the flat track which appeared to offer little assistance to any other bowler.
But, prior to the floodlights coming on, Ervine was the star turn with the highest one-day score by any batsman at The Rose Bowl.
Hampshire's victory takes them up to the shoulders of Worcestershire, who lead Group A on better run rate.
But Nottinghamshire still have two games left, the trip to Grace Road to face Leicestershire on Tuesday, followed by Wednesday's meeting with Hampshire at Trent Bridge (1045 BST).
If Notts fail to beat Leicester, Worcester would then be red-hot favourites to win the group by polishing off Ireland at New Road, also on Wednesday.
But, whatever the result on Tuesday, Wednesday's contest at Trent Bridge seems sure to be a private duel for the other Group A quarter-final place.
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