Wet and windy conditions made for a tough clash between the two struggling sides who are both in the bottom three, but it was Leeds’ defence which won the day, holding out against some more experienced players.
The Kent side took an early lead through stand-off Ryan Taylor-Dennehy’s penalty, but after a high tackle Leeds kicked their way level through Connor Lloyd on 10 minutes.
Lloyd added another penalty shortly after with Tonbridge pulled up for crossing, but it was 6-6 on 20 minutes following Tonbridge’s second penalty, Leeds being penalised for offside.
The first try of the match went to Harry Robinson, with Leeds having won a lineout on 22 minutes. Lloyd’s conversion made it 13-6.
But Tonbridge scored their first try just before half-time with Perry Parker touching down from a maul, and the conversion tied the game at 13-13.
Leeds were penalised for holding shortly after the game restarted, and Taylor-Dennehy’s penalty put them ahead, but another penalty from Lloyd levelled the scores at 16-16.
The breakthrough came with Tonbridge down to 14 men, with Leeds winning a lineout catch and drive, and Robinson racing in for his second which put them 21-16 ahead.
A fourth penalty for Tonbridge narrowed the gap, but the Yorkshire side held out for the win.
Rotherham Titans stepped up to second in National Two (North) after a 26-12 victory over Yorkshire rivals Huddersfield.
Former leaders Stourbridge suffered their first loss of the campaign and dropped down to fourth, helping both Rotherham Titans and Hull to climb the table with wins on Saturday.
The Titans took five points from the win with tries coming from scrum-half Sam Boxhall, second row Matt Smith, wing forward Zak Poole and No 8 Callum Bustin, while stand-off Matthew Minogue kicked three conversions.
For Huddersfield flanker Lewis Bradley and full-back Thomas Hodson scored tries and centre Will Milner added one conversion, but it wasn’t enough.
Hull ran in six tries on their way to a 38-19 victory at bottom of the table Blaydon and are now third.
Sheffield Tigers returned from Yorkshire rivals Harrogate with a 27-7 victory.
Harrogate scored first through wing forward William Seymour, stand-off Fox converting for a 7-0 lead at half- time.
But Tigers were soon off the mark with tries from replacement Simeon Meek, centre Jamie Broadley and right winger Robert Davidson.
Stand-off Mark Ireland did well on a windy day to kick all three conversions and two penalties.
Wharfedale boosted their fortunes with a close 15-14 home win over Loughborough Students.
Wing-forward Carlson scored their only try of the game, with the other being a penalty try with five minutes remaining.
Stand-off Davidson kicked a first-half penalty too.
Otley extended their unbeaten run in the North Premier division to 11 games with a 50-17 victory over Lancashire side Burnage on Saturday.
Flanker Luke Cole ran in four tries in the win, while others came from wing forward Adam Malthouse (2), left winger Alex Beaumont and scrum-half Joe Rowntree who also kicked five conversions.