NCL D2, Derby: Derbyshire 172-7 (45 overs) beat Hampshire 163 (44.3 overs) by 9 runs
Hampshire grabbed the final Division Two promotion spot despite a nine-run defeat to Derbyshire.
The Hawks looked set to reach the top flight comfortably after restricting their hosts to 172-7.
They were cruising at 143-3, but the last seven wickets fell for 20 runs, Kiwi Chris Harris taking two of them.
However, a two-point lead going into the match proved enough after rivals Middlesex were beaten by Durham.
With a patient 56, Australian Simon Katich became the county's highest scorer in a one-day league season, surpassing Chris Smith's 720 in 1984.
Derbyshire were left disappointed as an inferior run-rate saw them fail to avoid a place in the bottom five.
Doing so would have eased their draw in next year's C&G Trophy.
Derbyshire: M J Di Venuto (Capt), S D Stubbings, C W G Bassano
C Z Harris, D R Hewson, Hasan Adnan, L D Sutton (Wkt), G Welch
N R C Dumelow, Mohammad Ali, K J Dean.
Hampshire: N Pothas (Wkt), S M Katich, D A Kenway
J P Crawley (Capt), W S Kendall, J R C Hamblin, A D Mascarenhas
S D Udal, W P U J C Vaas, A D Mullally, J A Tomlinson.