Jones is a huge fan of the triple Lions tourist, whom he believes has no equals among his peers when it comes to ball playing ability and link play between forwards and backs.
The Cardiff Blues veteran returned to domestic action against the Ospreys last weekend after a lengthy lay off following shoulder surgery and has been fast-tracked back into the Wales squad for their autumn Tests against New Zealand, Samoa, Argentina and Australia.
And, unsurprisingly given his high regard for Williams' abilities, Jones has no doubt that his inclusion will be a huge boost for Welsh rugby.
"As an out-and-out seven, a very good footballer - probably the best footballing back-row forward in world rugby - Martyn's presence is one which Warren Gatland is delighted he has," Jones told BBC Wales.
"He's been out for a little while but he came in and seemed to have settled in immediately.
"He played the full game so he looks as if he's probably going to secure that number seven shirt."
As for Jones' own position of scrum-half, the former Swansea star is delighted to see the return of another player with Lions experience.
The absence of the most-recent Lions starter, Mike Phillips, provides an opportunity for 2005 Lion Dwayne Peel to reclaim his Welsh shirt.
"I'm glad to see Dwayne there," added Jones.
"I'm always a big fan of Dwayne Peel. I think he's looked very, very sharp the times I've seen him this year.
"He's a top-quality player and I think when he is available he'll be back in there pushing Martin Roberts and Gareth Cooper.
"We're always quite well blessed in that department and Dwayne just adds quality to a very good bunch."