Essex 107 for 1 (Mickleburgh 68*) trail Glamorgan 322 (Cooke 67, Goodwin 65, Masters 5-68) by 215 runs
Gautam Gambhir and Jaik Mickleburgh got Essex off to a strong start in reply to Glamorgan's 322 on the second day at Chelmsford, a match they need to win to maintain their promotion challenge.
They put on 95 in 23 overs before Gambhir fell victim to slow left-armer Dean Cosker but the home side steered clear of further trouble before the close to reach 107 for 1.
Both openers had punctuated the field with some fine driving and pulling before they were separated with Mickleburgh completing his half-century from 62 balls with the help of eight boundaries. He is due to resume on 68 accompanied by Greg Smith, who was yet score and arrived at the crease on the fall of Gambhir, who had scored 37 when he was caught at extra cover.
But with unsettled weather forecast for Thursday, it seems likely that the captains will have to come to some agreement to contrive a positive result. Certainly Essex will be hoping so because this is a match they must win if they are to keep alive their slender promotion hopes.
Earlier paceman David Masters claimed his fourth haul of five wickets or more in an innings this season, one of them being against Glamorgan in May.
After the visitors had resumed on 103 for 2, Masters was soon adding to his overnight two wickets by trapping Ben Wright lbw for 45 to bring an end a partnership of 107 with Murray Goodwin in 44 overs. He also got rid of Goodwin caught in the slips by Owais Shah as he pushed forward after the Zimbabwean had struck a solid 65 that had taken him nearly four hours. His 169-ball effort contained just five fours.
But Goodwin's departure only paved the way for the most entertaining partnership of the innings which featured Chris Cooke and Mark Wallace who went boldly for their strokes while gathering 95 in 21 overs against bowlers who, apart from Masters, struggled to find a consistent line and length.
It was broken when medium-pacer Ravi Bopara breached the defence of Wallace who had scored 38 and eight runs later, with the total on 234, left-arm spinner Monty Panesar claimed an lbw verdict to get rid of Cooke. His 67 came from 106 balls and included eight fours and a six.
John Glover struck an unbeaten 39 and Glamorgan reached 300 to claim their third batting point but that total would have been less imposing had Masters received better support. His unerring accuracy was illustrated by his figures of 5 for 68 from 36 overs, during which he collected his 50th Championship wicket of the summer.