While Daniel Hughes, Jake Lehmann and Cameron Bancroft also all chalked up half-centuries on Sunday's third day of the round-two program, Harris followed up his first-innings 125 by battling to 58no in the Red Rose county's second knock against Leicestershire.
It was a magnificent effort from the 33-year-old left-hander, coming in at No.4, Â as wickets tumbled around him and he had to simultaneously try to push the home side towards setting a challenging final-day target for Jake Weatherald-powered Leicester.
He'd batted for three hours, striking seven boundaries in his 124-ball vigil, but the match was still precariously balanced with Lancashire leading by only 124 with four wickets standing.
Hampshire looked en route to victory against Yorkshire, who were 5-65 still needing another 361 to win, thanks in part to a second excellent half-century in the match from Lehmann, fresh from his Sheffield Shield success with South Australia.
The 33-year-old followed up his first-innings 76 with 92 off 130 balls, frustratingly missing out on a ton, unlike his captain Ben Brown, who went on to make 103no following their 172-run partnership.
While Jake was doing his bit for Hampshire in the first division, dad Darren Lehmann looked on his way to overseeing a victory as Northamptonshire coach against Kent in the second division at Canterbury.
Following Nathan McSweeney's century the day earlier, another of Lehmann's favourite Australians Harry Conway took 5-36 to bowl out Kent for 178 and then took the prize scalp of England opener Zak Crawley for the second time in two days when they followed on. At 3-162, the hosts were still trailing by 344.
At Hove, 37-year-old Hughes, who's looked good since returning to Sussex, scored 83, peppered with 13 fours, as they chased a winning target of 328 against his fellow Tasmanian Beau Webster's Warwickshire, who had reduced them to 5-234.
Gloucestershire captain Bancroft, who'd had to watch Durham pile up 5-605 after he'd made the mistake of putting them in at Bristol, did his best to halt the visitors' victory march after his side had been forced to follow on, but once he was out for a stubborn 56 the hosts rolled over for 205, beaten by an innings and 225 runs.
Victorian Fergus O'Neill took his fifth wicket of the match as Nottinghamshire pushed for victory against Glamorgan, but rain interrupted their quest, with the Welsh side still battling hard on 2-132, still needing another 346 to win on the final day.
