Michael Cheek’s 64th-minute goal earned a 1-0 triumph for Andy Woodman’s men, who had finished 10th in the National League.
Dennis was forced to watch proceedings from the bench as an unused substitute, yet it remains an achievement to savour for the Ravens.
The 29-year-old, who spent a year on Pompey’s books, has endured a largely disappointing second spell with Bromley as he seeks to kick-start a stuttering career.
Hampered by injury, he featured just 23 times this season, while netted his only goal in their final National League fixture of the campaign in a 4-2 win at Barnet.
Indeed, much had been expected of Dennis after returning to Hayes Lane in August 2021, the club where he initially made his name.
An impressive 47 goals in 156 appearances during his first Bromley stay persuaded Kenny Jackett to snap up the attacking player on a free transfer in July 2018.
Yet his time at Fratton Park proved underwhelming, with eight appearances and one goal, as he struggled for first-team opportunities.
His sole League One outing was from the bench in a 2-1 defeat at Oxford United in January 2019.
Dennis marked his introduction by claiming an assist, supplying a right-wing cross which was acrobatically netted by Brett Pitman for the Blues’ consolation.
His only Pompey goal arrived at Southend in a 2-0 Checkatrade Trophy victory during their march to the final against Sunderland, for which Dennis was an unused substitute.
During the 2019 pre-season, Jackett intimated the former Watford apprentice had emerged as a strong contender to fill the number 10 role in the campaign ahead.
This appeared to be strengthened by two goals in the opening friendly – an 11-0 success at Irish side UCD.
However, in August 2019, Dennis was sold to Leyton Orient for an undisclosed fee after a year on the south coast.
In the subsequent two seasons, he netted four times in 49 appearances for League Two Orient, albeit with availability hampered by injury.
Having been released on a free transfer last summer, he once more linked up with Bromley, appearing in pre-season before signing a permanent deal.
Yet in the second half of the campaign he made just eight appearances, absences largely influenced through injury.
Still, Dennis ended it with an FA Trophy medal and Wembley victory as Bromley defeated promotion-chasing Wrexham 1-0.
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