Sussex were confirmed as Division Two champions when they collected a batting bonus point on the final day of their match against Middlesex at Hove.
Opener Tom Haines made 105 and James Coles an unbeaten 132 as the game, which saw no play on the first two days because of rain, ended in a draw when Sussex declared on 459-4.
Passing 250 in their first innings, in which they had earned three points for bowling out Middlesex on Saturday, had put their overall points total beyond the reach of second-placed Yorkshire.
Having resumed on 112-2, Haines and Tom Alsop took the score to 211 before the latter was dismissed by off-spinner Josh de Caires for 66.
Haines brought up a 161-ball century with a boundary off Luke Hollman, but the bowler brought his innings to an end in his next over, bowling him for 105.
At that point, Sussex were 233-4, but a Hollman no-ball to John Simpson carried the total past 250 in the 67th over of their innings.
The south coast team clinched promotion last week with an innings victory over Gloucestershire – their eighth of the season – and will play in Division One next summer for the first time since 2015.
With the title secured, Coles and Simpson extended their partnership to an unbroken 226, with the former reaching three figures for the first time this summer, hitting six sixes and nine fours in his 150-ball innings.
Middlesex used nine bowlers, including an over and a half from wicketkeeper Jack Davies, before the teams shook hands.
Simpson’s unbeaten 87 against his former side took his runs total for the season to 1,197, at an average of 74.81.
