Tom Bowen proved the Ospreys worst nightmare at St Helen’s as his first-half double inspired an emphatic Welsh derby win on Halloween.

The pocket-rocket wing crossed for two early tries to put the frighteners on the Ospreys and leave a partisan home crowd incandescent with rage.

Josh Adams collected in the corner for a third, and after weathering a storm in the second-half, the pack rumbled over to secure the bonus-point and give Tom Howe his first Cardiff Rugby.

It was the perfect evening for the battered and bruised Blue & Blacks, who were without 18 players due to international call-ups and injuries. They now finish the block on a high ahead of a return to Cardiff Arms Park to face on Saturday, December 5.

Cardiff made a bright start at St Helen’s with Le Roux Malan and Josh Adams carrying to good effect and the Ospreys unable to exit sufficiently.

They threatened to break the Ospreys on two occasions before a penalty kicked to the corner laid the platform for the opening try. The pack made the hard yards and put dents into the Ospreys defence with short carries before the ball was spread wide and Steff Emanuel’s long pass found Bowen in the corner.

Jarrod Evans converted to give the Blue & Blacks an early seven-point advantage but the Ospreys quickly went on the attack.

Ryan Smith swooped for a turnover penalty from the restart, despite his hands appearing to hit the floor first, but the Ospreys needed no second invitation and went to the corner.

A succession of penalties were awarded to the hosts and at the third time of asking Ben Breakspear showed no hesitation to give the try. However, following a TMO intervention, replays clearly showed Johan Mulder get under Steff Thomas to hold the ball up.

The Ospreys were playing with the advantage and went back to the corner but they were again held up over the line as Cardiff escaped unscathed.

Mark Jones’ men continued to benefit from 50-50 decisions and again went to the corner but a remarkable effort from Matty Young saw him keep his old Cardiff teammate Harri Wilde’s kick in and cleared long into the Ospreys half.

The Blue & Blacks struck for a stunning second try on 16 minutes, attacking with a set-play off the back of a scrum and Evans attacking the line. Bowen looped around the play-maker and collected a perfectly delayed pass to slice through. The electric wing dazzled his way to the line and dived in at the corner for a fine effort.

Evans again converted from the opposite touchline to give his side a 14-0 lead with an increasingly irate home crowd showing their frustration at every opportunity.

Cardiff almost added a quick-fire third after Paea’s delayed pass put Steff Emanuel through. He kicked ahead and the Ospreys failing to secure the bobbling ball. Mulder collected but he was held up as St Helen’s took a collective sigh of relief.

However, they were stunned into frustrated silence on 30 minutes when Adams collected a beautifully weighted Steff Emanuel grubber for his second try in as many weeks.

Evans fired marginally wide but the Blue & Blacks took a deserved 19-0 lead into the break. They had to weather an Ospreys storm at the start of the second-half but weather it they did before enjoying their own opportunities.

The home side went on the attack 15 minutes into the half and they continued to kick to the corner. Cardiff however, were managing to disarm the Ospreys’ best attacking weapon and when they went wide Adams and Matty Young combined to hold them up.

Replays showed Young was offside and the Swansea outfit again went to the corner, but Cardiff disrupted their lineout to again deny a rolling maul. The Ospreys eventually went wide but the Blue & Blacks continued to defend heroically with Tom Howe swooping for a turnover penalty with his first act.

A fifteenth penalty saw the Ospreys continue to lay siege in the Cardiff 22 and when the hosts worked their way to the five metre line a try appeared ominous.

However, Cardiff were given a reprieve when the Ospreys were penalised for a dangerous clear out and they were marched back a further 10 for back chat.

And after working their way down field, Cardiff kicked their own penalty to the corner and bludgeoned their way to the line with Howe the recipient.