Orissa all-rounder Biplab Samantray's fine spell kept defending champions East Zone in hunt for a berth in Duleep Trophy final as South were precariously placed at 134 for five at stumps on the second day after bowling out their opponents for 267.
Samantray took 3/22 in 14.1 overs as South Zone now depend heavily on their last recognized batting pair of left-hander Amit Verma and wicketkeeper CM Gautham who now need to add another 134 runs in order to get first innings lead.
Earlier, Saurabh Tiwary duly completed his century and scored a patient 145 off 267 balls and his partnership of 153 runs for the seventh wicket with Basant Mohanty (58) that helped them reach a decent enough total after being reduced to 66 for six on the first day.
Samantray, who is known for his ability to move the ball got rid of Karnataka trio of Robin Uthappa, Manish Pandey and Stuart Binny as South Zone seemed to be in a spot of bother after a solid stand of 69 between Robin Uthappa (40) and Abhinav Mukund (19).
But within a space of 10 deliveries both Mukund and Uthappa were back in the pavilion. Mukund was bowled by Bengal's left-arm spinner Iresh Saxena while Samantray got Uthappa who looked ominous having hit seven fours edge one to glovesman SP Gautam behind the stumps.
Ashok Dinda trapped Ramaswamy Prasanna leg before as South Zone were reduced to 71 for three.
Manish Pandey (31) and Amit Verma (22 batting) then added 44 runs as South looked like recovering from sudden collapse but Samantray struck twin blows.
First he was able to castle Pandey and then trapped all-rounder Binny leg before off the very next delivery but Gautham stopped the bowler from getting a hat-trick.
Brief Scores: East Zone 267 (Saurabh Tiwary 145, Basant Mohanty 58, A Mithun 4/68, S Binny 3/46)
South Zone 134/5 (Robin Uthappa 40, Biplab Samantray 3/22).