Purbrook had to settle for a tie at Idlers to keep their unbeaten record intact.
The visitors needed eight runs from the final over for victory but could only manage to tie the scores, after some inspired fielding by the hosts.
‘We looked like cruising to a win at one stage but in the end were glad to scrape a tie,’ said Purbrook captain Sean Figgins.
‘Idlers’ fielding hadn’t been the best but in the last over they pulled off a couple of blinding stops.
‘It was a pretty tense situation and one where you would rather be out there than watching from the sidelines.
‘We are a young side and I think it is an experience they will benefit from.
‘Next time we are in a similar situation then it might help us get over the line.’
Aaron Dean (two for 25) and Sam Pearce (three for 32) were the pick of the bowlers as Idlers were dismissed for 234 runs.
Openers James Holder (88) and Alan Mengham got Purbrook off to a good start in reply.
And with Lee Drennan (44) providing solid support at three it looked comfortable until things went awry.
‘We then had a bit of a wobble to say the least,’ said Figgins.
Portsmouth & Southsea picked up a third straight win with a comfortable seven-wicket success at Ellingham.
Skipper Dave Tiller (four for 19) helped skittle the New Forest side out for 155 and overseas player Ash Wallace impressed again with an unbeaten 90 as the visitors coasted home.
Locks Heath slipped to a surprise 126-run defeat at newly promoted Hook & Newnham Basics II.
Previously unbeaten Portchester lost to Ryde despite an unbeaten 40 from Lee Hungerford.
Fareham & Crofton tasted success for the first time by overcoming hosts Midhurst by five-wickets.
Hayling Island enjoyed a third successive triumph in division two.
Dan Mills (101 not out) and Sam Thompson (100 not out) put on a 183-run partnership for the third wicket, as they recorded an eight-wicket win over Southampton Community
Earlier, Mike Hallett grabbed four wickets for 50 runs as Community set a target of 240 for nine.