Burnside then took the lead with a total of 175 all out, while Old Boys ended the day at 13 for 1.
Burnside is currently ahead by 14 points over Lancaster Park, who also claimed first-innings points against Sydenham.
For Lancaster Park to have a chance at the title, they would need to win by an innings and hope Burnside doesn’t secure a win or a draw.
Theo van Woerkom’s four wickets and Josh McCarthy’s 77 runs helped Park reach 153 for five at stumps, leading Sydenham by nine runs in the first innings.
Heathcote declared at 253 for eight against East Shirley before limiting them to 83 for eight at stumps. St Albans also had a strong performance, posting 217 and bowling out Riccarton for 155.
All matches will resume at 10.30 am on Saturday.