Johnny Sexton's ability to predict what happens next on the pitch has ensured the World Player of the Year is peerless, according to teammate Chris Farrell.
The Leinster fly-half remains the talisman on whom Ireland hang their World Cup ambitions, with boss Joe Schmidt confident the 34-year-old will be fully fit for the Pool A finale against Samoa.
Understudies Jack Carty and Joey Carbery provide plenty of skill and panache at the backline's pivot, but none in green can rival Sexton at his spiky, demanding and ruthless peak.
Munster centre Farrell said Sexton takes visualisation to the next level.
"Johnny sees things unfolding before they happen; and that just comes from his experience, because he's seen so many things on a rugby field," Farrell said.
"We talk about doing work in the 'mind gym' to see things before they happen, or as early as possible as they unfold because we've seen it in our heads before.
"He's played so much rugby of such a high standard that he's naturally seen a lot of things happen, and he's able to see things earlier."
Sexton captained Ireland for the first time in Thursday's patchy 35-0 win over Russia where Schmidt's men sealed the bonus-point victory but precious little else.
The British and Irish Lions star laid on two tries before being withdrawn at half-time to sit on the bench and ice his troublesome thigh after the interval.
Ireland's reliance on Sexton has never been greater, but regular skipper Rory Best has always allowed the fiercely competitive playmaker the stage to make his points and lead the team in his areas of expertise.
Best, Sexton and company must still strike back from their damaging shock 19-12 loss to Japan by beating Samoa to secure a quarter-final berth.
That defeat by the tournament hosts leaves Ireland vulnerable to a last-eight clash with back-to-back world champions New Zealand.
While Sexton might be able to forecast events on the field, neither he nor his team-mates are in any mood to look ahead to knockout rugby.
But the 26-year-old Farrell still believes Sexton can command top billing at this World Cup.
"He's so exciting to play with because he gives you space and time on the ball," said Farrell.
"He's so consistent in what he does that you really know what you're getting from him every single time. He's a real leader and he's shown that again on Thursday.
"You know just during the week all the micro chats he'll be having, and not just with the same players over and over again, he goes and seeks players out.
"He gets what he wants out of them. He has so much experience and knowledge of the game that you have to take on board whatever he says.
"When you reflect on what he says you sometimes end up looking back at the video and realising he's dead right.
"He's so accurate in what he says to you. And he can make you a better player just by you talking to him."
