One wants to write his name in the record books as part of Chelsea's Invincibles, the other has been the invincible force in the rise of Manchester City.
And both bruising midfield behemoths could play a vital role in deciding the destination of the English Premier League title this season.
It is said that championship-winning sides often have a midfielder pulling all the strings together, and Nemanja Matic and Yaya Toure are the beating hearts of their respective sides.
They will be on show tomorrow morning (Singapore time) in the two key Premier League clashes, when Chelsea host Tottenham and City visit Sunderland, ready to drive their teammates on.
The Blues' Matic and City's Toure have become irreplaceable, even with all the talent at the disposal of Jose Mourinho and Manuel Pellegrini.
Both are perfect physical specimens, they are notoriously difficult to shake off the ball but both play different roles for their sides.
Toure was immense when City stormed to the title last season but he started this campaign poorly.
Paul Scholes went so far as to brand Toure as disinterested and lazy, but Pellegrini persisted with the Ivorian, perhaps knowing he would come good, or maybe knowing that midfield options Fernandinho, Fernando and James Milner could hardly fill the void.
Over the last two weeks, Toure has shown signs he's shaking off the lethargy with some good performances. City suddenly seem up to chasing down league leaders Chelsea, who have their own midfield inspiration pulling the levers in the engine room.
Mourinho's men look unbeatable now but it has helped that he has hardly had to tinker with his line-up because of injuries or suspensions.
Like City, Chelsea have no replacement for Matic.
It's hard to remember when Nigeria's John Obi Mikel last showed even a semblance of form, while Brazilian Ramires has been turned into a lung-bursting wide player.
In the 44 matches the Blues have played since the Serb's second coming from Benfica in January, Mourinho's men have won 69 per cent of the matches Matic has featured in and just 44 per cent of the ones he's missed.