Neil Jenkins has paid Wales captain Alun Wyn Jones a glowing tribute as he prepares to lead his country in Sunday's World Cup semi-final against South Africa.

Wales' record cap holder will make a 133rd appearance for his country at Yokohama International Stadium.

Lock Jones will move level with Sergio Parisse's career mark of 142 international games when his nine British and Irish Lions Test appearances are added, with only New Zealand World Cup-winning skipper Richie McCaw then above him on rugby union's all-time list.

"He has always wanted to be the best and strive to be the best, and over a long period he has achieved that," Wales assistant coach Jenkins said.

"He seems to get better with age. Wales have had some incredible rugby players, and he is up there as one of the best – if not the best – and we have had some great players.

"That speaks volumes for me. He is an incredible athlete, and there is no doubt that he is looking forward to Sunday.

"I don't know a 99 per cent Alun Wyn Jones, I only know a 100 per cent. It's 100 per cent or nothing, plain and simple.

"He is exceptional at what he does, he is an incredible player, an incredible leader.

"I was lucky enough to be involved with him in the (Wales) Under-21s back in 2006 in the Six Nations when we were in Ireland. You could see then he was a pretty special player.

"Whatever plaudits and accolades come his way he certainly deserves them. He is an unbelievable rugby player.

"He demands the best from himself and demands the best from the people around him. That shows in our environment and the way the boys go about their business, and they have got a leader they can look up to."

Apart from back-row forward Josh Navidi, who will miss the remainder of the tournament due to a hamstring injury, Wales will hope for a clean bill of health.

Centre Jonathan Davies missed the quarter-final victory over France three days ago because of a knee problem suffered in Wales' Pool D victory over Fiji earlier this month.

Jenkins added: "He seems OK. He is getting back to it, so I would like to think he is going to take a full part this week in training and obviously fit for Sunday.

"He is a key player for us, a big player.

"He trained most of the week last week, but didn't feel he was quite right. It's an important game on Sunday, and we need all hands on deck to get through that match."

South Africa knocked Warren Gatland's side out of the 2015 World Cup, winning a tense quarter-final at Twickenham, and both Wales' game and the England versus New Zealand last-four clash could easily go right to the wire.

"These semi-finals are huge games, they are going to be fiercely-contested and there won't be a great deal in them," Jenkins said.

"They could easily go to extra-time and sudden death (penalty shoot-out) but obviously from our perspective it would great to get it done in 80 minutes. I am sure South Africa feel the same as well.

"South Africa are an outstanding side. They are uncompromising, they are tough, physical and with some hugely-talented players.

"It's a very tough game for us, but we have done pretty well against them in the last few years.

"But Sunday is a different kettle of fish, a World Cup semi-final. We need to put it all on the line, basically."