Boyd Rankin boosted champions Warwickshire's hopes of beating Surrey with three wickets in an over on the third day at Guildford.
Rankin, who only joined the game on Friday after he was released from England's one-day squad, removed Zander de Bruyn, nightwatchman Stuart Meaker and Gary Wilson with the second, fourth and sixth balls of his seventh over as Surrey responded to Warwickshire's mammoth 631-9 declared.
Their plight worsened in the final over when Jason Roy (two) drove to cover where Jim Troughton took an excellent diving catch.
Surrey had lost four wickets for seven runs in five overs and closed on 269-7, 362 behind and still needing 213 to avoid the follow-on.
Their best hope appears to lie with former Australia captain Ricky Ponting, who finished unbeaten on 50.
Rankin had looked innocuous in his first five overs which cost 35 wicketless runs, but he returned to the attack to devastating effect as De Bruyn (17) was bowled off his pads, Meaker spectacularly yorked and Wilson (two) leg before to a ball which swung back in late.
With a day to go and the pitch still playing relatively well, Surrey should be able to escape with a draw but much will depend on Ponting, who looked in the mood to make another big contribution after scoring 192 on debut against Derbyshire last week.
Coming in after Vikram Solanki had become part-time off-spinner Ateeq Javid's first victim to the last ball before tea, Ponting began by hitting Javid out of the attack with two successive fours followed by a six over wide long-on.
There were four other boundaries in an 84-ball half-century which he reached shortly before stumps.