England Test captain Alastair Cook celebrated his new arrival with an unbeaten 139 as Essex took control of their LV= County Championship Division Two match against Derbyshire at a sun-baked Chelmsford.
The home side, though, were also indebted to some superb early bowling from David Masters, who took two wickets in four balls to complete a 29th first-class five-wicket haul.
Essex had been hurried out for 94 yesterday, but they hit back to dismiss Derbyshire for just 154 early on today, limiting the damage and clearing the way for Cook, whose first child was born 11 days ago, to show his class.
Essex got to the close on 297 for five, some 237 ahead going into day three.
Derbyshire had resumed with their lead at 45 runs on 139 for five, Shivnarine Chanderpaul unbeaten on 66.
The visitors, though, were immediately on the back foot as Masters made a breakthrough with the second ball of the morning when he bowled Richard Johnson for two.
Masters, who would end with 6-46, then sent David Wainwright back to the pavilion for a duck after he edged a delivery behind to James Foster two balls later.
When the former Leicestershire and Kent medium-pacer struck again in his next set-of-six, bowling day one hat-trick hero Tim Groenewald for two, Derbyshire were on the brink at 143 for eight.
Graham Napier saw off the tail as Mark Turner and Mark Footitt edged to second and third slip respectively without scoring.
Only West Indies batsman Chanderpaul had offered any sort of resistance, finishing unbeaten on 75.
Essex were back at the crease just before noon, with openers Cook and Jaik Mickleburgh, the latter of whom edged just wide of third slip when on 13.
The opener would add 11 more before edging to the slips when facing off-spinner Wes Durston’s first ball.
A single from Tom Westley saw Essex move on to 59 for one at lunch.
Following the restart, Cook, looking to put a disappointing winter Ashes tour behind him, went on to reach a 95-ball half-century, which included six fours.
Westley also passed 50, in just 70 deliveries, before he was bowled by Groenewald for 56 to leave Essex at 161 for two.
Ravi Bopara offered support to the England skipper as Essex moved their lead into three figures at 193 without further loss by tea.
— Debbie Knight (@debsknig) April 14, 2014
Cook's century finally arrived in the 61st over - just before 5pm - with Essex on double-Nelson at 222 for two, and his celebration included a tribute to his baby daughter.
Derbyshire, however, produced a late rally as, after Cook survived an edge behind that dissected wicketkeeper and first slip, Bopara fell two short of a half-century, caught at extra-cover off Wainwright, and Groenewald then trapped Greg Smith leg before with the new ball.
Masters lasted only four deliveries before he was out for a duck, caught in the off side to give Groenewald his third scalp of the innings and eighth of the contest.
But a rapid 13 from Ben Foakes - with three fours - helped move Essex closer to 300.