There were a few sleepless nights just over-thinking things - Henshaw
It says a lot about the importance of Robbie Henshaw that Joe Schmidt was willing to keep him in the squad despite knowing that he would play very little part in the pool stages.
The All Blacks made a similar decision with Brodie Retallick, while Eddie Jones also picked Mako Vunipola and Jack Nowell, who were all struggling with injury.
Another head coach might not have been as patient with Henshaw but it was a calculated risk that Schmidt felt was worth taking.
While the Ireland players were given the weekend off, Henshaw was slaving away with his rehab as he steps up his recovery from the hamstring issue that he picked up a few days after landing in Japan.
The 26-year-old is expected to return to full training this week with a view to featuring against Samoa on Saturday.
Unfortunately for Henshaw, he is no stranger to the treatment room, but his ability to hit the ground running after coming back from injury is one of the reasons why Schmidt didn't replace him in the squad.
Pressure It does, however, mean that there is even more pressure on the Athlone native to deliver.
"I'm finally back on my feet now, I'm looking forward to the next few weeks," Henshaw says.
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"I was training at the captain's run (last Wednesday) and on my feet for two weeks. I have been working in the gym and on the pitch - doing speed work and a bit of rehab as well.
"It has been good. I have been doing more rugby-specific stuff in the captain's run and full training next week, so it is good.
"I have to say, it has been tough sitting in the stands watching the games. I'm chomping at the bit really to get out and help the lads. It's exciting for me.
"There were a few sleepless nights, just over-thinking things - the ifs and buts. But once you see yourself improving and hitting those targets that you put down, that gives you the reassurance that you are coming good.
"There were a lot of stories going around that I was flying home and I had to get surgery and stuff, but that wasn't the case.
"It was a bit of a scare at the time, just a small tweak in the hammy. I had a previous injury there, that's why there was concern over it.
"But when we had the scan, it actually wasn't too bad, so that gave us confidence to make sure I could turn it around in a couple of weeks.
"If push came to shove I could have played (against Russia), so that was positive."
Injuries at various stages to Henshaw, Chris Farrell and Bundee Aki has meant that Garry Ringrose has played all three games thus far.
Schmidt has hardly ever had all four centres fit and available at the same time, which has meant that his hand has often been forced in terms of the make-up of Ireland's midfield.
After the warm-up games, it seemed as though Schmidt may have been leaning towards pairing Aki and Henshaw together but Ringrose has rediscovered his best form and has been excellent at the World Cup.
When it comes down to it, Schmidt may well end up going for a horses-for-courses selection with Aki arguably more suited to playing South Africa, while Ringrose's agility would be useful against New Zealand.
Regardless of which way Schmidt goes, it seems very likely that Henshaw will be one of the centres. He acknowledges that a lot of faith has been put in him.
"Yeah, yeah I know. But to be honest, it is good for my confidence that the lads see value in me and they have kept me here.
"I think I can add value to this group. I have a bit of experience on my shoulders so it is good to be here and help the lads.
"There is always an expectation on you. You have to be on top of your work all the time. You have to be prepared for what's coming up. That's always the case when you step on the field.
"It's about sticking to your processes and your routine to make sure you deliver.
"It's intense because you are working against the clock. I had a few days to get myself back on my feet and get moving. There is no real time to sit around and keep the head down.
"It's tough because you need to hit markers on certain days and thankfully that has been the case. That's positive."
Ireland's defence has largely been good and Henshaw's return would certainly help improve it again.
He has the benefit of playing with Ringrose most weeks with Leinster, but Henshaw also has a very good understanding with Aki from their time together in Connacht.
It's a selection headache that Schmidt would certainly welcome at the business end of a World Cup.
Ireland will get one more chance to iron out any kinks this weekend before a potential quarter-final rolls around.
"I think the defence has been pretty good, it was really good against Scotland and then really good in parts against Japan," Henshaw adds.
Mindset "You could see our mindset when Japan took the intercept off Jordan Larmour's pass and see Keith Earls scramble back.
"That's what I suppose defence means to us as a team. We work our asses off for each other and scramble. We never give up the chance.
"That was a huge positive in the Japanese game, we got back, we scrambled and we kept them out and we secured a losing bonus point.
"The defence has been a positive for us but we need to keep bringing it to a new level because teams are going to get better as the competition goes on.
"Unfortunately in the World Cup you only get one shot at it. We executed off a planned move (against Russia) but then there were a few handling errors in the 22.
"Probably just a little bit of patience is what I think we need to have and a bit of calm on our shoulders."