Rymell ton leads Essex into One-Day Cup semis
The 20-year-old made 121 off 130 balls after the early loss of Alastair Cook.
He was eventually bowled by George Hill (3/51) but Simon Harmer and Aron Nijjar shared an unbroken stand of 50 in 3.4 overs to see Essex to 317/7.
Yorkshire were all out for 188 in reply and Essex will now face Glamorgan in the first-semi-final on Monday.
The match will be played in Cardiff but having won the County Championship and T20 Blast in 2019 and Bob Willis Trophy last summer, Essex remain in contention to add their first 50-over silverware since 2008.
Essex: 317/7 in 50 overs (Rymell 121, Wheater 34, Westley 33, Hill 3/51)
Yorkshire: 188 in 38.4 overs (Revis 42, Luxton 34, Westley 3/33, Plom 3/34). (BBC)