Essex 268 (Bopara 61, Westley 57) and 22 for 1 (Mickleburgh 12*) lead Leicestershire 243 (Robson 74) by 47 runs
England bowling prospect Jamie Porter survived a serious bout of the yips to help Essex keep Leicestershire firmly in check at Chelmsford.
Porter pulled out in his delivery stride four times in a row as he attempted to bowl the third ball of his fifth over.
Even when he did release the ball at the fifth attempt, the final steps to the crease were short and stuttering. Two balls later, however, he rapped Paul Horton on the pads and had the opener lbw for 19. The 23-year-old's celebration was akin to Stuart Pearce exorcising his demons after netting a penalty in the shoot-out against Spain at Euro 96.
Porter was helped through his nightmare by words of encouragement from veteran seamer David Masters standing at mid-on. He bowled a sixth over in his opening spell before returning later, claiming a second wicket, and finishing with figures of 2 for 61.
Masters said: "There is not a lot you can say when someone runs in and they don't know what to do, and he's run in three or four times. He said to me, 'Hod, I don't know what's happening'. I said, 'Just relax, chill'.
"He had a hard day today and that is part of cricket and part of the learning experience. It's not all about running in and knocking people over - he's had a lot of that. He's been getting lots of wickets and bowling really well. He will learn from that.
"But taking the wicket was perfect for him - he said he'd had it planned all the time!
"I haven't had anything like that in my career, so it's sometimes hard to understand. It's a little bit of a mental block sometimes, worrying about things. But he overcame it out there and I take my hat off because that is quite hard to do. He could quite easily have chucked the towel in.
"There are a lot of people who have had it, but he is a strong lad, a strong character, and he'll be fine. He had a bad day. He bowled a lot of no-balls and he struggled. But we all have days when we struggle. It's a good learning curve for him; it'll be good for him going forward."
Porter had been mentioned in dispatches as a future England bowler when he followed a memorable first season in the county game - when he took 50 wickets - by adding 28 more in his first six Specsavers County Championship matches this summer.
But it was the tight and parsimonious bowling of Masters and Ravi Bopara that prevented Leicestershire racing away and overhauling Essex's first-innings total. Both bowlers claimed three wickets, Masters for just 33 runs from 19 overs, Bopara for 43 in 21 overs.
From the high point of 128 for 1, Leicestershire lost their last nine wickets for 115 runs in 43 overs. That they got within 25 runs of Essex's total was thanks to a 135-ball 74 by opener Angus Robson. His third half-century of the season included 10 fours.
Porter's had been the last Essex wicket to fall at the start of the day's play. Clint McKay sent two of his stumps flying with the 17th ball of the morning to finish with figures of 4 for 47 and Essex all out for 268.
After the departure of Horton, Angus Robson and Neil Dexter put on 88 for the second wicket in 25.2 overs without due alarm and with some crisp hitting.
Dexter was first to go for 33 from 72 balls when Matt Quinn ripped out his off stump soon after lunch. Robson was fourth man out when he top-edged Masters to James Foster.
In between Leicestershire captain Mark Cosgrove had become the first of three victims for Tom Westley at second slip, steering the ball straight into his hands as if giving him pre-match catching practice
Aadil Ali wafted outside off stump to give Westley a second catch, and Ned Eckersley completed the trio as Westley fell backwards to give Masters his third wicket.
Mark Pettini, making his first appearance at Chelmsford since moving to the Midlands last year, batted pleasantly for 80 balls, six fours and 36 runs before he fell lbw to Bopara.
Five runs later, Bopara accounted for Ben Raine, caught behind. McKay then scooped Porter to Dan Lawrence at point, which is where Rob Taylor perished soon after, to wrap up the Leicestershire innings.
Essex lost Nick Browne in negotiating 11 tricky overs at the end, bowled by McKay for 8. But Jaik Mickleburgh and nightwatchman Quinn saw them through to the close.