Ed Joyce struck hundreds in both innings of a game for the first time in his career to put Sussex on course for back-to-back Division One victories on day three against Warwickshire.
The Irish opening batsman countered Ian Bell's brilliant unbeaten 189 at the start of the day with a fluent 125 not out as Sussex closed 57 runs away from victory on 273-2.
Stand-in captain Bell had earlier given Warwickshire more than a glimmer of hope of victory by moving on from his overnight 144no to set Sussex a testing victory target, or so it seemed, of 330.
However Joyce, fresh from 117 in the first innings, took the game away from Warwickshire in the afternoon, sharing a century opening stand with Luke Wells (57) and then contributing to a lively unbroken partnership with Rory Hamilton-Brown (48no) after tea.
After kicking off the 2014 season with an emphatic innings victory over Middlesex, Sussex are now strong favourites to make it two wins from two when play resumes at Edgbaston on Wednesday.
All three outcomes still remain possible at Lord's, however centuries from Sam Robson and John Simpson have made Middlesex favourites heading into the final day against Nottinghamshire.
Robson moved on from his overnight 144no to post 163 before becoming one of three victims for Notts pace bowler Andy Carter, while Simpson struck an unbeaten 108 down the order before a declaration came with Middlesex on 439-9, 113 ahead.
Steven Finn then claimed three top order wickets to take his tally for the season to 14, Phil Jaques, James Taylor and Samit Patel all falling to the England seamer.
Champions Durham will look to push for an opening victory over Northamptonshire after establishing a second innings lead of 252 on day three at Wantage Road.
Seamers Usman Arshad (4-78) and Jamie Harrison (3-83) shared seven wickets as the hosts were bowled out for 378, with 97 from Matt Spriegel holding up their victory charge.
Then Durham were able to push on to 178-5 and open up the possibility of a challenging declaration on the last morning, despite 4-39 from veteran off-spinner James Middlebrook.
At Taunton, Somerset reignited their hopes of victory after racking up 530-9 against Yorkshire, who were finally dismissed for 450 the previous day.
An impressive all-round batting performance - five home players passed 50 and Craig Meschede is closing in - was underpinned by Johann Myburgh's 91 on debut, but a draw remains the most likely outcome.
Myburgh added impetus in the middle order alongside Lewis Gregory (69), while Craig Kieswetter (63) and James Hildreth (67) also tucked in to the toothless Yorkshire attack.