Centuries from Aneesh Kapil and Alex MacQueen earned Surrey a sizeable first-innings lead over Northamptonshire on the second day of their Second XI Championship contest at Guildford on Wednesday.
Kapil (123 not out) and MacQueen (109) boosted the hosts to 522 all out in reply to the County's 341 - a 181-run advantage for Surrey.
Gemaal Hussain (4-107), Yassir Abbas (3-111) and Saif Zaib (2-103) all plugged away manfully in the Northamptonshire attack.
The County will resume on Thursday morning on 32-1 in their second innings, still trailing by 149 with a day to go.
Anyone planning to head down to Surrey for Friday's one-day Trophy match should note it's now being played at Charterhouse School.