The striker, signed from the Solent Churches League, struck four times in the second half as Rovers thumped Wymering 6-2 in the Billy Hill Cup final.
It was 1-1 at the interval but Eyinju was unstoppable going down the slope at Horndean’s Five Heads Park after the restart.
‘Salako was absolutely unplayable,’ said Rovers boss Chris Yoxall. ‘He’s lightning quick and every time we broke they were never going to catch him.
‘At 3-1 up I thought that was it, but then we got a fourth and fifth in quick succession - it was brilliant.’
Eyinju has only recently joined Portchester, having been enticed over by Solent Churches colleagues Chinemerem Nwokenkwo and Ikponmwosa Obasuyi, who joined Rovers mid-season.
Konnor Higgins had put Portchester into the lead before an error by keeper Tom Allen - who punched clear instead of catching the ball - led to Wymering levelling just before half-time.
Eyinju took control in the second half, scoring four goals in a row to put his side 5-1 ahead. Though Wymering bagged a second, Higgins tapped in Rovers’ sixth late on. Jack Hill and veteran Dan Cunningham netted consolations.
Portchester endured a dismal league season, picking up only two points from 12 Division 1 matches and scoring just 13 goals.
They did beat Burrfields early on but fielded Higgins when he was not registered and were subsequently docked the three points.
One of their two points came via a 0-0 stalemate with Wymering, after Allen was sent off early on.
Rovers enjoyed a bye to the Billy Hill Cup semi-final, where they came from 1-3 down to draw 4-4 against Mob Albion. Trailing by two goals in the penalty shoot-out, they ended up winning thanks to three spot-kick saves from Allen.
‘We had a fairly traumatic league season,’ recalled Yoxall, ‘but we’ve got a team now. We’ve found a goalkeeper, we’ve found some strikers. Everyone’s buzzing for next season already.
‘The Wymering manager (Paul Critchett) said to me, ‘if you can keep this side together you’ve got a proper, decent team.’
Yoxall admits Portchester deserve to start next season in Division 2 after finishing bottom of the top flight in 2021/22.
The league structure, though, is unknown as yet and will depend on how many new clubs are admitted and if any current ones drop out.
‘I’d prefer one big league with more games,’ said Yoxall, ‘but I think the league would prefer two divisions if they can.
‘Maybe it would be a sensible step for us to be in Division 2 next season, face some new teams, and try to rediscover the winning habit. Who knows?’
Rovers’ cup final success was the club’s first silverware since they won Division 1 of the Portsmouth League in 2016/17.
The centre half pairing back then was Jamie Peters and Paul Leggett. And Yoxall was forced to partner them again in central defence in the cup final when Dan Richards withdrew due to Covid.
Leggett, who had been playing in midfield since rejoining from Harvest, could now remain in defence again when the curtain is lifted on next season.