England's Farrell could shatter Grand Slam dream
And this weekend is not different – the pair will be central figures when the Irish bid for a Grand Slam at Twickenham on Saturday.
The two formed a highly effective midfield duo during the British and Irish Lions drawn series in New Zealand last year.
But that will all be forgotten for at least 80 minutes at Twickenham on Saturday when Ireland, already crowned Six Nations champions, attempt to record just a third Championship clean sweep to set alongside their 1948 and 2009 triumphs.
They may not be direct opponents, with Sexton at flyhalf and Farrell deployed by England at inside centre, but both men are key playmakers for their respective sides.
That Ireland are in a position to complete a Slam owes much to Sexton's nerveless last-ditch drop-goal, which on the back of superb work by his forwards, sealed a come-from-behind victory over France in their tournament opener.
It was an example of Sexton's ice-cool demeanour but the 32-year-old is far more than a kicking machine.
Crucially, as with all good players in the crunch No 10 position, it is the Leinster star's ability to make the right decision under pressure, whether to kick or pass, that has been a hallmark of his 78-cap career.
So too has been the ability to withstand the knocks that come from being a targeted player, with Sexton a key on-field lieutenant for coach Joe Schmidt.
Sexton, struggling with a gluteal muscle injury, missed 10 points with the boot in Ireland's 37-27 win over Wales in Dublin on February 24.
But he was close to his best during Ireland's four-try 28-8 win over Scotland last time out.
"He's been incredible in camp this time around," said Ireland skills coach Richie Murphy.
"He always has been, but he's really driven the lads hard, and worked with a lot of the young players, and taken a leadership role that we always knew he was good at," Murphy added.
Farrell, six years younger than Sexton, was in superb form at the start of the Championship, kicking expertly out of hand during England's 12-6 win over Wales.
But Farrell's role as the 'second' playmaker outside flyhalf George Ford, has been affected by his childhood friend's loss of form this season and indeed, in England's recent back-to-back defeats by Scotland and France, by those of his forwards at the breakdown.
Playing with a limited and slow ball is one of the hardest things to do in the cauldron of Test match rugby and, unsurprisingly, Farrell has found life tough of late.
Indeed Farrell has been switched to flyhalf late in matches by Jones as a result of Ford being off-form and in Paris, last week the Saracens star, who raised eyebrows for his role in a pre-match tunnel flare-up against Scotland, found himself with the added responsibility of captaincy in the absence of injured regular skipper Dylan Hartley.
But Farrell was unable to either adjust England's game-plan or inspire his teammates out of their insipid display sufficiently to score the four tries they needed for a bonus-point win that would have kept their title hopes alive.
However, in the closing minutes, Farrell almost guided England to a win, if not by a bonus point, by initiating the move for Elliot Daly's late try and then kicking a superb conversion.
"Farrell was finally playing without the shackles, his own imagination at the helm," wrote former England flyhalf Stuart Barnes in the Sunday Times. "It had taken panic stations to bring England to within the brink of a comeback.
"In those final minutes, we saw a fantastic player, not a fantastic captain,"
But with Hartley set to resume as captain, England will hope the "fantastic player" on show in Paris is also in evidence against Ireland.
Agence France-Presse