The forwards had the edge in a keen contest but the difference was in the backs where Tonbridge showed extra speed and clinical finishing.
The Kent team scored six tries and five conversions to Chi’s four tries and four conversions.
A bonus point was won for tries but it was academic as London Irish Amateur thumped Thanet to secure second place.
Chichester may feel disappointed as they had a win and a draw against Irish, plus a much superior points difference, but they look forward to the Sussex Trophy final on May 7 against East Grinstead.
Chi attacked from the kick off, Phil Veltom carried and the pack drove hard to the left corner. The ball went out to the centre before a knock on and scrum to Tonbridge.
Liam Ferguson received a yellow card for retaliation as Tonbridge reacted to more pressure from a lineout. Blues won their lineout again and Jack Smallman, Scott Barlow and Adams threatened, forcing a home infringement. The penalty was in front of the posts but was hooked wide.
Now it was Chi being challenged as TJs attacked and their fly-half and centres were tackled, but after two drives, winger Nauer dived for the line and although it was said later that he had been short, the try was allowed, with Redman converting.
Eddie Armah was forced out, Rob Lawrence made a lot of ground, and Moses Kasujja was tackled after an exciting run from the scrum.
TJs counter-attacked and handled skilfully across the pitch for a final offload to score again and convert.
However, from a line-out and well-organised drive, he touched down for Chi’s first try with Richard Adams adding the extras.
But TJs showed their class when they hit back immediately. A long throw to the back of the lineoutgave their elusive scrum-half Hamlin a chance and he took it brilliantly with pace and two sidesteps to plunge over.
The conversion meant 21-7. An Adams high kick was carried on by Ferguson and Ben Robson,setting up a determined driving maul by the pack which was killed by a TJs defender as it crossed the try line.
A penalty try awarded and Adams’ conversion meant that it was 21-14 at half-time and all to play for.
Chi scrum-half Jack Walker had taken a knock and Jon Reid replaced him. It was important not to concede an early score but it happened. Swift passing by TJ’s back line with Sykes offloading with deft flick gave them a fourth try and extras.
The Chi scrum was beginning to get on top and their lineout ball was safe in the hands of Nick Blount and Barlow. But the TJ’s throws to their rear jumper and quick ball to their outsides posed constant threat.
A penalty to them and a thrust by the fly-half was stopped, but the move resumed and the ball flashed across for the fifth try to make it 33-14.
Ferguson had to go off with a shoulder injury and had been replaced by Phil Dickin, while Josh Pszczonka also came on for Nick Shopland. The forwards turned the screw and TJs held the ball on the ground to prevent a possible try, escaping penalty.
Barlow was held up on the line from a maul. Chi scrum pushed them back, Kasujja picked up and gave the ball to Dickin to finish off under the posts with Adams converting.
But Tonbridge hit back once again as Hamlin spun like a top out of a tackle and raced over from 20 metres, meaning a 40-21 lead after the conversion.
A penalty was kicked to the corner, lineout and drive and Lawrence crashed over for a deserved score. An excellent Adams kick from wide out to gain the extras.
Blues finished strongly, a tribute to their fitness and spirit.
A lightning counter attack put TJs winger away and it needed a huge tackle by Golds to prevent a certain try. There were robust moments and TJs loose head was sent off for elbowing as Chi came through.
One last assault saw Armah forced out by the home defence which had survived a tricky 20 minutes.
Final score 40-28 after a gruelling contest with a high standard of rugby. Chi have scored 846 points this season with 316 against in 26 games. They amassed 123 tries and have had the best defensive record in the league despite this defeat. Congratulations to the squad and coaches.
CHICHESTER: Shopland, Lawrence, Veltom, Blount, Barlow, Ferguson, Polhill, Kasujja, Walker Adams, Armah, Smallman, Fairbairn, Robson, Golds, Pszczonka, Dickin, Reid.