A step or two slower than they used to be, with families to take care of and with nagging injuries to nurse, the champions of a decade ago continue to light up the ATP Tour with as much fight, determination and sublime skill as ever.
As they come to the end of their playing careers, the tour's elder statesmen continue to battle through the long, arduous seasons, hoping to get their rankings back to a position where seeding might help protect them in the early rounds of tournament draws.
If they can manage that, their chances of recapturing their former glory increase significantly. And no one believes in them more than they do.
Still blessed with the same weapons and shot-making ability that propelled them to the top of the game, they are still a danger to any player at any event.
The current top four, or anyone else for that matter, never want to see the following names in their side of the draw at the Masters 1000 or Grand Slam events, and for good reason.
But to get back to where they enjoyed their best playing days, it takes a lot more than one or two shocking results—it takes a season's worth of consistent wins.
The top 10 is a very tough nut to crack, but the following players have all been there before and know what it takes to survive at the very top.
Can any of them perform at the level needed, and for the time needed, to make a return to the top 10?
These are the players who, in my opinion, have the best chance.
*All players are aged 29 or over and have been former Grand Slam/Masters 1000 event champions.