Ashwell Prince became the first Lancashire batsman in 16 years to score a century in each innings of a match as the visitors turned the screw against Kent by building a mammoth 417-run lead in Canterbury.
Already promoted as Division Two champions, Lancashire, who have yet to suffer a defeat during this season’s LV= County Championship, declared late in the day on 393 for five to leave themselves 10 overs and the final day of the season in which to wrap up their ninth win of a triumphant campaign.
Kent, who lost veteran opener and first-innings top-scorer Rob Key to a fractured left thumb when fielding in the gully earlier in the day, reached stumps on 32 for one after losing emergency opener Daniel Bell-Drummond lbw for eight in Oliver Newby's final over.
The hosts now face the tough prospect of batting out the final day in order to save off their third defeat of the summer.
Earlier, Lancashire openers Paul Horton and Luis Reece - resuming on their overnight total of 75 without loss - took their partnership through to three figures inside 45 minutes before Reece departed for 47, easily stumped by understudy wicketkeeper Sam Billings after being beaten by the flight from James Tredwell.
Visiting skipper Horton sneaked a sharp single to mid-on to reach a patient half-century from 145 balls as he and Prince battled through to a lunch total of 140 for one.
The second-wicket pair upped their tempo after the interval, with Prince recording a 107-ball fifty, while Horton posted his third hundred in four championship matches since returning from a twice dislocated finger on August 2.
His run of form came to an abrupt end when, on 106, he edged an attempted dab down to third man against Darren Stevens into the hands of James Tredwell at slip.
In tandem with Prince, Horton had helped add 167 in a little over 50 overs for the second wicket to help take the visitors 283 for two at tea.
But wickets fell in the evening session as Karl Brown raced down the pitch to Tredwell only to slice an aerial drive high to Matt Hunn at mid-off before Luke Procter heaved across the line to go leg before to Stevens.
Prince then became the first Lancashire batsman since John Crawley in 1998 to hit hundreds in both innings of a match when he reached three figures with a rasping off drive against Tredwell.
Soon after, Prince cut hard at a short one from teenage debutant Hunn but found a thick edge to be superbly caught by a tumbling Billings to make it 348 for five.
Andrea Agathangelou marched in to smash three fours and two sixes in a 35-ball fifty against a tiring Kent attack to spark the declaration with half-an-hour of day remaining.