With first-choice out-half Sexton failing to shake off a calf strain, 25-year-old Jackson will make his first Championship start since his rookie campaign in 2013 when Ireland begin their 2017 challenge in Edinburgh.
Today’s game will also mark Best’s 101st Test cap and the start of his second Six Nations as captain since succeeding Paul O’Connell and after a third-place finish in last season’s tournament for a team transitioning after the 2015 World Cup, the hooker believes he is better placed to put his trust in new additions to the team.
“Eventually you grow into it a little bit and you learn to relax, and trust people the around you,” Best said yesterday following Ireland’s light training session at Murrayfield. “That’s certainly something I’ve realised over the last 12 months.
“We’ve had a few tough times with injuries but when that happens and you see how boys step in, it shows that there is a massive trust.
“We’ve built a big squad but now is the time to see if boys can step up. We talk about the squad, and to lose a player like Johnny, even early in the week, but can Paddy step up and be better than he’s been for Ireland?
“That’s what it’s going to take and that’s what the whole idea of the squad is, that guys who think they’re maybe not going to play don’t relax and keep pushing on. Jacko has done that from what I can see but ultimately it’ll be in the Test match (that’ll be the test).”
Best is determined that Ireland drive on from their impressive November performances when he skippered his team to wins over New Zealand and Australia, never mind the 2015 title-clinching victory at Murrayfield.
“The thing we’ve always talked about is not dwelling on the past. We take a quick look back at the past to make sure it drives us forward and I think if we start looking back to two years ago and what we achieved, we’re standing still.
“I felt we stood still a little bit last year in the championship and we have to make sure that all the work we put in to make it a good autumn just gone, we need to make sure we push on with that.
“And the only way we can make sure we push on from that is to look back and say: ‘We did this well and that well, we didn’t do that so well’, that’s what we need to improve on.
“I think Scotland in Murrayfield, it’s a really, really tough place to start, but what a way to see if we pick up from where we left off and improve. “And we are going to have to improve on the performances we produced last November.”