William Johnson-Cole scored for the third successive league game as Sevenoaks Town stretched their unbeaten run to four matches at rainy East Court on Saturday.
Johnson-Cole was involved in both the major incidents in the game, firing the Oaks in front after 15 minutes, and then conceding the second half penalty that earned the West Sussex hosts a share of the spoils.
Oaks suffered a blow losing skipper Frankie Sawyer after only 33 minutes with an ankle injury, joining Sam Crabb, Ryan Fowler and Danny Cumbers on the injury list.
Goalkeeper Ben Bridle Card continued his excellent form, pulling off a fine early save as Grinstead made a lively start.
Sawyer never recovered from suffering an early knock inside the opening 10 minutes and replaced by Kenny Pogue.
Jack Miles had a header cleared off the line, before Johnson-Cole put Oaks in front after 12 minutes with a right foot finish, converting Alec Fiddes’ corner.
Bridle-Card made another fine save at one end while opposite number Sheikh Ceesay pushed away Fiddis’ free-kick at the other.
Grinstead got back into the game nine minutes after the break.
Johnson-Cole tussled with defender Karn Miller Neave who went to ground in the box referee Alex Bradley pointed to the spot and booking the Oaks player, before George Landais beat Bridle-Card.
The game’s tempo increased in the second half, despite the weather, with surface water appearing on the near touchline.
Oaks had chances to win the game in the final half hour.
They had a two-against one, with Pogue free on the left as Johnson-Cole burst away, only for a defender to cut out his pass.
Osman Proni fired over, then Bridle-Card tipped Landais’ effort over the bar.
Pogue’s shot was blocked, then stand-in captain Tom Ripley went close to converting Luke Coleman’s free kick.
Oaks also went very close to grabbing a late winner - Pogue and Ripley denied after Proni’s corner caused problems in the home box in the last action of the game.