One moment you're sitting on the bench, next you're haring down the wing setting up a try, next you are galloping over the line for a third try in a stunning 10-minute salvo.
Welcome to the world of Tommy O'Brien.
There were question marks when the Leinster back was named among the replacements on a 5:3 bench split.
An out and out winger, O'Brien had a night to forget against France in Paris in round one and was left off the panel for the nervy win over Italy.
Wings James Lowe and Robert Baloucoune were two of Ireland's best performers against the Azzurri but head coach Andy Farrell sussed that the aerial battle would be crucial against England and recalled O'Brien for his eighth cap.
And when Lowe pulled up with a groin injury in the 18th minute, with Ireland leading 3-0, it was immediately clear his day was done.
And soon after O'Brien whipped off the training top he came off his wing to run a support line for Baloucoune in the build-up to Jamison Gibson-Park's try.
Ten minutes later the roles were reversed as the Ulster man skipped out of a tackle and offloaded to O'Brien, who raced in. The conversation gave Ireland a 22-0 lead.
🏴0-22 ☘️
— RTÉ Sport (@RTEsport) February 21, 2026
Try three 😱😱😱 Tommy O'Brien runs in the latest. Baloucoune finds a gap in the English defence and hands off to O'Brien.
📺 @rte2 and @rteplayer https://t.co/b2OI4OoWVJ
📻@rteradio1 https://t.co/Od8FxnL2On
📱Updates https://t.co/YXqp4pbqKj pic.twitter.com/2zXbFHGtqN
"Sometimes it's about where you just get thrown into it, sometimes you don't have time to think," said the 27-year-old, who made 64 metres and two line breaks off seven carries.
"I haven't been on the bench in a while but you forget that when you're on the bench, you're thinking of everything, watching everyone, seeing how they're getting on.
"Still, it's no fun sitting on the bench. So just being thrown into it, you don't have time to think about it.
"You just go in and start playing another game of rugby.
"We needed that [performance].
"That was something that we said, just making sure that the first 20 minutes we absolutely fire into them.
"I actually ended up getting on after 20 minutes, it wasn't something I expected.
"But I just said, fire into it and give it an absolute crack."
O'Brien was one of a handful of players who spoke to reporters in the mixed zone in the bowels of Twickenham an hour or so after the full-time whistle went on a famous 42-21 win.
"It's awesome and in stark contrast to two weeks ago," he said of the mood in the victorious dressing room.
"Somehow we just knew that it wasn't where we should be and what we hold ourselves to.
"So the feeling of just sitting in the changing room with your team-mates after it, when you know you've put on a proper performance and emptied yourself, is incredible."
After Ireland soaked up early English pressure the sizeable minority Irish support among the 81,953 began to make themselves heard over the locals.
"That's something we definitely don't underestimate, giving the Irish people these special days and how special it is to us to provide these special moments," said the Dubliner, who now has six international tries.
"[It's] so special. I know it's a bit of a cliche, but we really do have the best fans in the world.
"When you see how many people are in the stands, how happy everyone is, how proud everyone is to be Irish, that's unbelievable."
