Harry Finch’s battling half-century meant Sussex just had the better of an absorbing first day in their Bob Willis Trophy encounter with hosts Middlesex at Radlett.
Finch batted for more than three hours to hit 12 fours in a top score of 69 out of the visitors’ total of 293 all out.
Delray Rawlins weighed in down the order with a run-a-ball 46, but Sussex’s day was marred by a back injury to opener Tom Haines, who returned late in the innings with a runner, but looked in great discomfort.
For Middlesex, there were four wickets for all-rounder Martin Andersson (4-77) and Blake Cullen, making his debut for the county, aged 18, returned figures of 2-51.
With the score 211/5, Rawlins and Ollie Robinson stabilized matters again with a stand of 35 before Cummins returned to trap the latter LBW to one which looked a little high.
Rawlins cut loose with an enormous six over the old pavilion off Walallawita and three successive fours from the returning Andersson.
The young all-rounder gained revenge when Rawlins holed out to Nick Gubbins on the fence, but his swashbuckling effort had edged Sussex ahead of the game once more. Rawlins hit 5 fours and 2 sixes in his inning.