Mal Loye defied Sussex for five-and-a-half hours at Hove to keep Lancashire in control of their own destiny as they seek a first uncontested county title for 72 years.
Loye (148 not out) came in at the fall of the first wicket and was still there to bat out the final over from Yasir Arafat as Lancashire reached the nail-biting safety of 290 for nine to earn a draw.
Sussex lead the title race by one point but are sure to have been overtaken by the time they resume their pursuit of a second title in four years. While they are inactive next week, Lancashire play their match in hand against York-shire at Old Trafford.
At Canterbury, Kent batsmen Robert Key and David Fulton spectacularly denied Hampshire.
The pair were undefeated on the final day, with Key and his fellow opener putting on 281 before the captains agreed to end proceedings. Key made 136 runs from 312 balls, including 17 boundaries, while Fulton's 134 came from two fewer deliveries but contained one more four.
Hampshire captain Shane Warne was so frustrated that he asked wicketkeeper Nic Pothas to bowl, in his pads, with the second new ball.
In Division Two, Anil Kumble spun Surrey to their seventh win of the season, taking eight for 100 from 34.2 overs as the leaders beat Northamptonshire by seven wickets. Kumble finished with match figures of 11 for 183 and Surrey knocked off the 65 runs they needed from 16 overs with 12 balls to spare.
It took Essex less than 24 overs to take the remaining six Somerset wickets for their fifth win of the season, by 211 runs. Once Cameron White fell for 111, the last five wickets fell in a little more than six overs, with Mervyn Westfield and Tim Phillips claiming five wickets.