Initially selected at full-back for the New Year’s Day clash against Ulster in the URC at the RDS, O’Brien was ultimately a late withdrawal from the game and it was confirmed a week later that he was due to spend several months on the sideline with a neck injury. This ruled him out of Ireland’s successful defence of their Six Nations crown and a plethora of provincial fixtures, but the Kildare native finally made his return off the bench in Leinster’s tense Champions Cup semi-final win over Northampton Saints at Croke Park the weekend before last.

He was subsequently named on the left-wing for the Blues’ comprehensive victory against Ospreys in Ballsbridge on Saturday and in addition to claiming a third-minute breakthrough try, O’Brien delivered an all-round performance that helped him to secure a player of the match award.

“With the neck I knew it was going to be long-term and I wasn’t certain when I would be back. It’s all dependent on scans. It was frustrating because with a hamstring you know it’s six weeks or something like that and have a deadline. Whereas this one, I was kind of waiting and waiting for scans to be positive,” O’Brien remarked after Saturday’s game.

“It definitely took a little bit longer than I was hoping, but I’m just delighted to be back. I’m feeling very fresh, the shoulders feel good for once. There is that benefit, I just need to get up to match fitness and that 80 minutes helped.”

While a superb 70-metre solo effort by O’Brien during the early exchanges of the contest was followed up by Ross Molony’s first score in a Leinster jersey since January 2022, Osprey fired back impressively with a converted five-pointer from Owen Watkin and a penalty try just shy of the first-quarter mark.

Ciaran Frawley was yellow carded for tackling Luke Morgan in the lead-up to the latter, but in his absence, Jordan Larmour bagged his first try of the night on 27 minutes to propel Leinster towards a 21-14 interval cushion.

This put the hosts in sight of a bonus point and following excellent approach work from O’Brien, South African lock Jason Jenkins crossed over for their fourth try within 60 seconds of the restart.

The final outcome was placed beyond doubt when Larmour was released by Robbie Henshaw for his second try in the 54th minute, but Leinster continued to inflict damage on their Welsh counterparts in the final-quarter of a game that was played in front of 15,750 spectators.

In addition to Larmour completing his hat-trick, Jamie Osborne, Charlie Ngatai and Tommy O’Brien also added their names to the scoresheet as the eastern province cruised over the line.

Now just a single point adrift of Glasgow Warriors in the URC standings, Leinster will look to bolster their quest for top seeding in the knockout rounds of the competition when they face Ulster at Kingspan Stadium in Belfast this Saturday – seven days before their Champions Cup final showdown against Toulouse in London.

“Away in Ulster is always tough. I’ve played a couple of games up in Ravenhill. It’s obviously a good atmosphere, but pretty hostile against you when you’re up there,” O’Brien added.

“It’s always good to play in, but it’s a tough place to go. Then obviously with Toulouse in the middle we know that, but we’ve a good squad of players to hopefully manage it.”

Scorers for Leinster: Tries – J Larmour 3, J O’Brien, R Molony, J Jenkins, J Osborne, C Ngatai, T O’Brien. Cons – R Byrne 5, C Frawley 3.

Scorers for Ospreys: Tries – O Watkin, Pen Try. Cons – D Edwards.

LEINSTER: C Frawley; J Larmour, J Osborne, R Henshaw, J O’Brien; R Byrne, L McGrath; A Porter, R Kelleher, T Furlong; R Molony, J Jenkins; R Baird, J van der Flier, C Doris.

Replacements: D Sheehan for Kelleher, J Conan for Molony, J Gibson-Park for McGrath (all 52), M Milne for Porter, T Clarkson for Furlong (both 56), C Ngatai for Byrne, T O’Brien for Henshaw (both 58), S Penny for Doris (71).

OSPREYS: M Nagy; L Morgan, O Watkin, K Williams, K Giles; D Edwards, R Morgan-Williams; N Smith, D Lake, R Henry; J Ratti, H Sutton; H Deaves, J Tipuric, M Morris.

Replacements: G Thomas for Smith, T Botha for Henry (both 52), J Morgan for Deaves, S Parry for Lake, J Walsh for Edwards (all 57), V Sekekete for Sutton, E Boshoff for Williams (both 71).

Referee: S Grove-White (SRU).