Ned Eckersley hit his second century of the season to help Leicestershire post 328-4 on the opening day of their Division Two clash with Essex at Chelmsford.
The visitors made the most of having first use of a friendly pitch, Eckersley leading the way as he reached stumps unbeaten on 133 from 236 balls.
Essex must have feared the worst when they lost the toss and saw Leicestershire's opening pair of Greg Smith and Niall O'Brien put on 91 with ease.
Tymal Mills eventually made the breakthrough, the left-arm paceman forcing O'Brien to play on to his stumps after making 51 from 54 balls with the help of eight boundaries.
Smith followed soon afterwards for 46 when he despatched a long hop from leg-spinner Tom Craddock into the hands of David Masters at deep mid-on, leaving the score at 102-2.
Leicestershire looked in danger of letting their good start go to waste when Joe Burns was bowled by Mills, reducing the Foxes to 115-3 in the 35th over.
However Eckersley and Shiv Thakor put on a partnership of 97 in 28 overs to steady the ship and put the conditions into perspective.
Thakor departed for 36 when he became Craddock's second victim of the day but Eckersley carried on through to three figures - by the close he had hit 15 fours and two sixes having been at the crease for just shy of five hours.
Skipper Matt Boyce helped add an unbroken stand of 116 for fifth wicket and will resume on the second morning with 37 to his name.