Nemanja Matic and Yaya Toure are their teams' heartbeat
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.
The 26-year-old reads the game superbly, is deceptively quick and powerful in the tackle, is a good passer of the ball and has stamina to burn to cover swathes of green for 90 minutes.
And Matic is confident, declaring yesterday that he aims to help Chelsea emulate Arsenal's Invincibles of 2003/2004 by finishing the season undefeated.
He has been the sturdy foundation upon which a more aesthetically appeasing Chelsea have been built.
Just ask Cesc Fabregas, who has racked up 13 assists and two goals playing alongside Matic.
Or Chelsea captain John Terry, who has called imposing midfielder the "complete player".
Matic has already drawn comparisons with France and Chelsea legend Claude Makelele, the man synonymous with the holding midfield position. But he is more than just a holding midfielder, the Serb is a hybrid of Makelele and Toure.
Adept at the defensive duties which made the Frenchman famous, he also bears the traits of the City star - good passing skills, a stinging shot and a powerful dribbling style.
That's no surprise considering he started out as a more offensively minded midfielder who adapted his game to suit Mourinho's needs.
They might perform different roles, but Matic and Toure are prototypes of the same machine, programmed to swat aside slight tiki taka merchants and humiliate them with the hellish marriage of finesse and fury.
In his days at Olympiakos and Monaco, Ivorian Toure was more of a defensive midfielder, before completing his evolution as a powerful playmaker at City. His 24 goals and 11 assists for the Citizens last term bear testament that it was a successful experiment.
Sure, the passing of younger brother Ibrahim in January and the infamous pout about the lack of attention on his birthday messed with the mental wellbeing of Toure.
But his recent displays have suggested that the midfield monster is alive again. And that's good news for City, because without their heartbeat running strong, their title hopes would have flat-lined very quickly.
- Age: 31
- Height: 1.89m
- Weight: 90 kg
- Country: Ivory Coast
- Club: Manchester City
- Position: Midfielder
- EPL goals (this season): 3
- Shots: 31
- lAssist: 1
Scored in back-to-back EPL games for the first time since March in the 3-0 win over Southampton. He’s never scored in three straight league games.
- Age: 26
- Height: 1.94m
- Weight: 84kg
- Country: Serbia
- Club: Chelsea
- Position: Midfielder
- EPL goals (this season): 1
- Shots: 9
- Assist: 2
Chelsea have won 24 of 35 matches with Matic in the squad. In the nine matches without him, they have won just four