Thomas took 4-13 off eight overs as Triangle collapsed to 54 all out at Cams Hill School in Division 5 South East of the Hampshire League.
Thomas’ previous best league figures had been 3-3 against Fareham & Crofton 4ths in 2019.
Captain Harry Robbins (2-17) had removed both openers - Ben Jones (4) and Tristan Nay (9) - before new ball partner Thomas ripped out the middle order.
Doug Noyce (3-13) dismissed Paul Godfray (18) - the only Triangle batsman in double figures - and cleaned up the tail.
After opening the bowling, Robbins also opened the batting - top scoring with 19 before becoming one of four Portchester wickets to fall.
They still romped to a six-wicket success, though, with the winning runs coming off the second ball of the 14th over.
Hambledon 3rds openers Jonty Oliver and Jamie Lewis were agonisingly close to maiden league centuries at Steep 2nds.
Teenager Oliver was dismissed for 98 and Lewis ended 96 not out with the pair sharing a 199-run stand.
Oliver’s previous highest league score had been 88 against Compton last year, while Lewis’ best had been the 90 he compiled against Hursley Park earlier in the month.
Hambledon posted 236-2 before every member of their seven-strong bowling attack took at least one wicket as the hosts were bowled out for 162 to lose by 74 runs.
Kevin Wingham (2-14) and Joel Eastment (2-25) were the most successful with Matt Sabben-Clare top scoring with 48 before he was run out by Oliver.
There were two century partnerships for the first wicket in a tense encounter between Kerala 2nds and Havant 3rds at Hayling Park.
After Kerala had opted to bar first, Rakesh Janardhanan (88) and Roshan Radhakrishnan (50) put on 145 for the first wicket.
The breakthrough came in the 31st over with Noel Baiju (2-31) dismissing both openers in the space of four balls.
Havant’s bowlers continued to struggle with only Martin (1-50) and Hayward (1-26) getting a wicket before Kerala finished on 215-4.
The visitors’ reply got off to a solid start with Tom Wragg (60) and Julian Atkins (35) putting on 102 for the first wicket.
A 70-run partnership for the third wicket between Sam Woodgate (27) and Andrew Ransley kept Havant in the game.
The fifth Kerala bowler used, Harikrishnan Korasseril (4-28), produced a key spell when he dismissed Woodgate, Will Udy and Matt Hayward in the space of 11 runs.
Though Ransley (51 not out) reached a half-century, Havant closed on 209-5 to lose by six runs and fall to fifth in the table.