For three days he forwent sleep in order to put an ice pack on his ankle every two hours and the reward was a starting berth in the quarter-final victory over Ireland. No wonder, then, that Wales' 'ice man' shed a few tears at the end of the 22-10 triumph in Wellington.
"It is hard to put into words what it means. There were a few tears and that at the end, but we won't let it go to our heads," said Lydiate.
"We are out here to do a job and, come tomorrow, we have got be getting ready for next weekend. I was gutted to get injured, but it is part and parcel of the game. There was a chance I would be going home, but I tried to do everything in my power for that not to happen.
"I was just so happy to get on the field against Ireland. I did no more than anyone else would have done. It was about being diligent with your icing times and being on time with your physio appointments. Every rugby player would be the same, I guess."
Lydiate's tackle count and close quarter work allowed his fellow young bucks in the Welsh back row, skipper Sam Warburton and Toby Faletau, to do some roaming work and the balance of the Welsh side was back to where it was for the first one and a half games.
He did what head coach Warren Gatland had asked him to do in the dressing room before the game and "empty his tank". He came in for special praise for his efforts as Gatland explained that "he was so tired after the game he couldn't take his shirt off, but he did what we asked."
Next up is a battle against French skipper Thierry Dusautoir and another massive contest as Wales seek to reach their first World Cup final.
"I didn't leave anything in the tank because it was all about getting the result. Every time you put the jersey on that's what you want and we are all just so happy," added Lydiate.
"We had been through the mill pre-season and we backed our conditioning. In the first 40 minutes we defended for our lives and our conditioning really pulled us through.
"The Irish back-row are big, powerful men and it was a case of trying to stop them before they got going. Once they get going the likes of Sean O'Brien and Stephen Ferris take a lot of stopping.
"At half-time it was a case of just keeping going. We had to keep our composure, we kept plugging away and the boys really put their hands up in defence."
Now that he is back in the fold Lydiate can't wait to get back onto the field to make up for lost time. But he knows the stakes have risen since he was last in the side.
"We are in the semi-finals now, it's knockout rugby and we have just got to push on. We've got to get on with it and not get ahead of ourselves," added Lydiate.
"I just wanted to go flat out as long as I could, chuck my body in there, and I got through it, just about. There is a lot of talent within the squad and we've worked hard all summer.
"We are one big, tight unit and we work hard for each other. They called our pool the 'Pool of Death' and I think our conditioning really helped us. We haven't picked up too many injuries and from here on in it's about not leaving anything in the tank."