The final score suggests that this was a comfortable win for the league leaders but in fact they trailed at half time and the result was in doubt as late as the 60th minute.
With confidence boosted by some new recruits and a win on the road at Pocklington the previous week, the hosts started strongly and, throughout the first period, it was difficult to tell which team was top of the table and which was struggling near the bottom.
Hoppers’ defence was certainly put to the test and the first quarter saw play switch from end to end and a yellow card for centre James Fitzpatrick on 30 minutes did little to help the visitors’ cause.
As the half drew to a close, Park spurned a kickable penalty to set up a five-metre lineout which paid dividends as hooker Stuart Brown was driven over to give his side a deserved 5-0 lead at the break.
Hoppers went on the attack from the restart dominating up front and replied in kind as Sam Gale touched down from a lineout drive to level the scores.
But from the kick-off, a mix-up in defence gifted a try to Dave Hall and the full back’s conversion from the touchline regained the lead.
Hoppers at last got their act together with some strong forward drives and, when the ball was released, Scott Jordan made the most of a wayward pass to put Niall Crosley in at the corner.
The kick again failed but the momentum was now with Hoppers and, after a quick tap penalty gained ground, Ally Murray broke from a maul near halfway and rounded the cover to touch down and get the lead for the first time at 15-12.
Park attacked from the kick off but Crosley seized on a loose ball on his own 22 and outpaced the defence for the bonus point try.
Hoppers now turned the screw on a tiring defence, and two trade-mark tries from No.8 Matt Lamprey, one converted by replacement kicker Sam Stott, secured the win.
Coach Paul Arnold, pictured inset, said: “All credit to Birkenhead, they wanted it more than us in the first half but I was confident at the break that we would get our act together, look after the ball and get the five points. As league leaders, we are there to be shot at and teams will raise their game accordingly.”