Essex limited-overs captain Ryan ten Doeschate has said it remains a mystery why his side have struggled in the County Championship.
Victory over Middlesex on Friday made it six wins from seven T20 Blast games to stay top of the South Group.
But they have one victory and six draws from nine Division Two matches.
"For some reason we're still lacking in four-day cricket. We haven't quite worked it out," all-rounder Ten Doeschate told BBC Essex.
"It's a continual uphill struggle that we will pursue and try and get better. But to bounce back in T20 is crucial for the team morale."
Essex's sole County Championship win came on the opening day of the season against Derbyshire, but a loss by an innings and 470 runs to Hampshire last week made it eight games without a success.
It is in stark contrast to their T20 form, which sees them five points above the cut off point for the quarter-finals.
"Getting six wins out of seven early on is crucial," said 33-year-old Dutch international Ten Doeschate.
"It's a competition we haven't generally started well in and we're always playing catch-up.
"We won't be focusing too much on how many wins we need. We're trying to make a culture and a way of playing."