That led to O’Brien – who was close to a Wales call-up for 2026 Six Nations – getting his big shot in between experienced scrum-half Richie Rees and stalwart centre Ashley Smith.
“It was my first season being in the senior environment,” said O’Brien, who finished with former South Africa fly-half Morne Steyn as his opposite number.
“I was a young kid and I suppose it gave me confidence because it was a great experience. I’d only really played for Cross Keys before that so to have a start out at Stade Francais and get a win out there was massive.”
Stade, who are third in the Top 14, have rotated their squad for the fixture against Dragons but boast formidable depth and will expect to earn a home quarter-final against either Zebre or Pau.
However, Dragons have been a tougher nut to crack this season and go into the fixture fresh from spirited showings against Stormers and Lions in South Africa.
“They’re a very good team and are going really well in the Top 14 but it’s an exciting challenge we are all looking forward to,” said O’Brien, who passed 500 points for the club last weekend.
“They are very dangerous and a good attacking outfit but it’s an exciting opportunity in the knockout stage and we are ready to get after it.”