Lionel Messi appears to be nearing a sensational exit from Barcelona this summer, with Manchester City leading the race for his signature.

Barca's greatest ever player handed in a transfer request last week but the process of him actually leaving the club is likely to be complicated.

Messi claims that he should be allowed to leave on a free transfer and has subsequently refused to return to pre-season training, whereas Barcelona argue that the contractual clause in question expired in June.

Even if the 33-year-old is granted a free transfer, very few clubs in world football could then afford his weekly wages.

Man City appear to be one of those who could, and a move to the Etihad Stadium would see Messi reunite with Pep Guardiola, under whom he played the best football of his career at Barcelona.

Here, Sports Mole takes a closer look at the Argentine's incredible record under Guardiola.

Messi has played more matches - and unsurprisingly therefore scored more goals - under Guardiola than he has under any other coach in his career.

The attacker featured in 219 games for Barcelona while Guardiola was in charge, and incredibly scored 211 goals in that time, in addition to registering 97 assists.

In total Messi therefore had a direct hand in 308 goals from 219 matches during Barcelona's most successful era, and the peak came in Guardiola's last season at the helm.

The 2011-12 campaign has proven to be the zenith of Messi's illustrious career, breaking the European record for most goals in a season with a staggering 73 in just 60 games across all competitions.

That tally included 50 in La Liga - another record - and saw the iconic number 10 become Barcelona's leading goalscorer of all time too.

It was by no means a one-off, though; Messi scored 53 goals the campaign before, 47 in 2009-10 and 38 in 2008-09, steadily improving already impressive totals year on year under Guardiola.

Perhaps most impressive of all, Guardiola's four years in charge of Barcelona earned Messi four Ballons d'Or - the only player in history to have won the prestigious award four times in a row.

Messi has gone on to be named the world's best player 'just' twice more in the following eight years, which still makes him the most decorated player in its history but showcases a drop-off from the Guardiola era.

Now 33, the attacker is desperate to win the award again and reportedly believes that Guardiola will be the man to help him do so - a deduction it is difficult to argue with considering his past record.

As far as team silverware is concerned, Messi also enjoyed his most fertile period under the Spanish boss, winning 14 trophies including two Champions Leagues and three La Liga titles.