It meant they retained third spot, on 20 points — two ahead of Napier Marist, three behind Port Hill United and seven behind City Rovers Seconds.
Thistle are now fifth-equal with Eskview United and Hastings Western Rangers. All are on 12 points, although Thistle and Rangers have a game in hand — their deferred fixture, which will be played in Gisborne on Saturday.
Napier adapted to being a player short against the Jags by simply having only one man up front, with a midfield four and a back four giving them parity in those areas.
It meant that if Thistle were to make their extra man count, they had to push forward from the back.
Rightback Max Mika did this to best effect, and it was his run that drew the foul for the free-kick that midfield flank player Hector Araya floated in for Tilley’s goal.
Napier’s line-up was depleted by a remarkable set of circumstances.
O’Neill said three of the squad were in Taiwan with a New Zealand masters’ team, one player was supporting his wife and newborn child, another could not travel because it was his turn to look after his children, another had a hamstring injury, and yet another had relatives visiting.
“Eight of those boys who played today are eligible for under-19s,” he said.
The other two were 42-year-old centreback Regan Cameron and 33-year-old defensive midfielder Willie Stanger. Their experience came in handy under difficult circumstances.
Otherwise, O’Neill thought that territory and possession were “pretty even’’.
Thistle coach Garrett Blair said he didn’t want Napier’s depleted state to influence his side’s approach, but it probably did a little bit.
Nevertheless, Thistle were the first team to beat Napier in the league this year, and continued to be unbeaten at home this season.
“We’ve done everyone else in the top half of the league a bit of a favour with this result,” Blair said.
The game was evenly contested, with Thistle’s best first-half chances coming in the 33rd minute, when centreback Chris Spurr’s 40-metre effort was just over, and in the 42nd, when striker Jake Theron crossed low from the right, just ahead of onrushing strike partner Araya.
Stanger had the first good shot of the second half, a 30-metre piledriver well saved by Thistle goalkeeper Mark Baple.
Then came Tilley’s goal, just reward for the midfielder’s outstanding performance, both in the air and on the ground.
For much of the game, Thistle used strikers Theron and Araya as wide players, with Davie Ure in particular — but also Nicky Land and Tilley — making attacking runs from deep.
It’s a tactic that can give late-arriving midfielders more space to set themselves for a shot, but Napier’s Stanger and centrebacks Kaeden Atkins and Cameron were alert to the danger. The sure tackling and speed on recovery of Atkins were outstanding.
Ander Batarrita was the other Thistle midfielder, operating wide on the left, where he and fullback Daniel Venema combined well to thwart many Napier raids and set up counter-attacks.
Napier’s lone striker, Fin Smith, had a tough time of it, up against in-form centrebacks Liam Ryan and Spurr.
Smith had support from central midfielder Zac Madsen and wide men Leyton Ross and Ethan Clarke. Napier were lively but the Thistle rearguard generally stood firm. When Napier got shots away, Jags keeper Baple was hard to beat.
In the 58th minute, Baple stopped one snapshot with his legs; in the 70th he narrowed the angle and battered away a shot from Madsen, then spread himself to foil the rebound attempt. When he was beaten, in the 79th, Ryan cleared off the line.
At the other end, Napier keeper Dan Robinson had to look sharp, too. He turned a shot from Araya past the post in the 56th and saved from Land in the 80th, but was relieved to see a 64th-minute back-heel stopped on the line and a 67th-minute Ure shot hit the post.
Max Logan came on for Araya in the 63rd minute and slotted into the midfield, allowing Ure to move forward. Emerson Araya came on for Venema in the 82nd minute, and Sam Hogan came on for Batarrita in the 88th.
The referee was Andy Parker, of Napier.
Against Maycenvale, Gisborne United went 1-0 up after 10 minutes. Left-flank midfielder Josh Harris shot with the outside of his right foot from the edge of the penalty area. The keeper palmed the shot away but right midfielder Noy Paull was following up and scored from six metres.
In the 35th, player-coach Corey Adams scored with a firmly hit free-kick past the wall into the bottom right corner from the edge of the penalty area. Younger brother Josh had run over the ball, faking a shot into the left corner to get the keeper moving that way.
In the 65th, Dane Thompson ran on to a lay-off from Josh Adams and “laced it” into the bottom left corner from 30 metres.
Less than 10 minutes later, defensive midfielder Mal Scammell capped a strong game by getting forward on the right and cutting the ball back from the byline into the path of the flying Harris, who sidefooted home from close range at the far post.
Maycenvale were awarded a penalty for handball in the 85th minute and scored from the spot.
United started well, had a 20-minute lull, then finished the first half strongly.
Their second-half performance was more dominant, to the extent that their third and fourth goals were scored while skipper Kieran Venema was off in the sin-bin being trialled in this league.
Kieran Higham and Venema continued their good form as double centrebacks, while the man-of-the-match award went to leftback Malcolm Marfell, whose solid defensive game was complemented by his link play with wide midfielder Harris.
Rightback Lucian Nickerson hardly put a foot wrong until he went off in the 75th minute for Matt Adams, whose arrival was delayed by the road closure caused by the fatal road accident at Wainui.
Paull and Harris were dangerous on the wings and Thompson impressed in the middle.
Up front, Josh Adams did not add to his tally — he has 17 goals from 10 league games — but had a hand in two of the goals.
Goalkeeper Jack Faulkner did not have a lot to do, but made two good saves early in the match.
The referee was Chris Niven.