When Lionel Messi smashed a 30-yard free kick past a man many consider to be the world's best goalkeeper during Wednesday night's Champions League semi-final against Liverpool, he took one step closer to fulfilling his own prophecy that he would bring the trophy back to Camp Nou this season.

In his first campaign as captain of Barcelona, the maestro looks set to lead the club to a treble, which would also be his third three-trophy haul under his third different manager at the Catalan outfit.

An eighth La Liga title from the past 11 years is already in the bag and a Copa del Rey final with Valencia awaits later this month, but it is the Champions League that they really want, having seen arch-rivals Real Madrid dominate the competition in recent years.

It looked like things could be nervous for them in next week's return leg at Anfield when they led Liverpool 1-0 heading into the final 20 minutes at Camp Nou on Wednesday, with Messi relatively quiet compared to his usual other-worldly standards.

However, in the space of just seven minutes the Argentine took the tie away from last season's beaten finalists, first showing his poacher's instinct to finish off a fortuitous second and then turning an average (for him) display into one which will be talked about for years by picking out the top corner from 30 yards and leaving Alisson Becker no chance.

It would have been a stunning goal in any game at any level, but to produce it in the closing stages of a Champions League semi-final - and bring up 600 career club goals in the process - was the latest in a long line of incidents marking Messi out as quite possibly the greatest to have ever laced up a pair of boots.

Only seven players in the history of football have scored 600 goals at club level; Messi joins an exclusive and star-studded club which also includes Cristiano Ronaldo, Pele, Romario, Gerd Muller, Ferenc Puskas and Josef Bican.

The 31-year-old will be forever entwined with his fellow footballing immortal Cristiano Ronaldo, but he took 128 games fewer than Ronaldo did to reach 600 goals and actually hit the milestone quicker than it took Ronaldo to make it to 500.

Messi's greatness is most readily compared to Ronaldo's as they are playing in the same era, but the argument of who is the best of all time will forever rage on and in those stakes one must look beyond purely goals.

There is no doubt that the Argentine is one of the greatest goalscorers - and, for that matter, one of the best scorers of great goals - we have ever seen. However, beyond that seven-strong list of players to have reached the 600 mark there are many who prefer the flawed genius of a Diego Maradona or George Best or the unparalleled influence of a Johan Cruyff or Alfredo di Stefano.

Yet Messi is surely the one player who performs best over a spread of the quantifiable aspects when selecting football's GOAT.

Whatever the metric, Messi is always near the top. Who else can boast dribbling as unstoppable as Maradona or Garrincha, goalscoring as relentless as Pele or Puskas and passing as perfect as Xavi or Andres Iniesta?

Add to that the longevity of Barca's number 10, whose 600th goal came 14 years to the day after his first - a staggering average of almost 43 goals every year of his professional club career. Maradona only made it past 30 goals in a season once in his career, whereas even Pele only passed the 43-goal figure seven times in official matches.

This is the 10th season in a row in which Messi has scored 40 or more goals across all competitions, and he looks set to pass the 50-goal mark for the seventh time in his career having scored 48 in just 46 appearances already - this at the age of 31, when logic suggests he should be slowing down.

Perhaps the best example of how much we have come to expect from him is that a season which saw him score 34 goals in 36 league games en route to a domestic double, and 45 goals in 54 games across all competitions, was regarded as so poor that he came fifth in the voting for last year's Ballon d'Or.

While those who finished above him - Luka Modric, Cristiano Ronaldo, Antoine Griezmann and Kylian Mbappe - all enjoyed memorable campaigns for club, country or both, to suggest that Messi was only the fifth best player on the planet in 2018 is farcical.

Messi is making a mockery of that and is already the clear favourite to scoop the prestigious award for an unprecedented sixth time this year, as well as leading the race for a record-breaking sixth European Golden Shoe.

Yet it is his team success - which now holds such weight in the Ballon d'Or voting - which will mean most to the player, and there is no doubt that Barcelona and Spanish football are living in 'the Messi era' at the moment.

Since breaking into the senior set-up 15 years ago, Messi has helped Barcelona to 34 trophies with two more still up for grabs this season - making up more than a third of their all-time haul of 91 in their illustrious 121-year history. By contrast, Real Madrid have won 'just' 20 trophies in that time.

The Argentine is already one of the most decorated players of all time and shows no sign of slowing down, having won 10 league titles, four Champions Leagues and six Copas del Rey among his countless other accolades.

The glaring absence in that endless list of achievements - and the main counter-argument to Messi being the best ever - is his lack of silverware at international level.

It has largely been a tale of heartbreak for Argentina during the Messi era, winning only Olympic gold in 2008 and finishing as runners-up in the Copa del Rey on three occasions, as well as at the 2014 World Cup.

Pele has three World Cup crowns to his name while Maradona almost single-handedly won one for Argentina, but Messi is still the highest scorer in his country's history and won the Golden Ball at the 2014 World Cup.

Messi will be 35 by the time the next World Cup rolls around so his best chance to claim the holy grail may well have passed him by, although in this era the Champions League is arguably a more accurate measure of sustained class rather than a tournament once every four years.

Comparative World Cup failings cannot be extended to a suggestion that Messi goes missing in the big games either; he is the leading scorer in the history of both El Clasico and Barcelona derbies, while other La Liga high-fliers Sevilla, Atletico Madrid and Valencia complete his list of top-five most favoured opponents.

There are a myriad of records and stats which could be listed on top of this to further strengthen the argument of Messi's claim to the throne, but perhaps the most important one cannot be quantified - how he makes fans feel when at his very best.

Opposition supporters have given him standing ovations and there are things he does on the football field that the mere mortals watching him - both in the stands and on the field - can barely fathom.

It is those moments - the ones which make the hairs on your arms stand on end - which will be the fondest memories of Messi when he does eventually hang up his boots, and incredibly he seems to produce them on a near-weekly basis.

Wednesday's strike - his eighth direct free kick goal of the season - was one of them, having also produced another for the 500 landmark with a last-gasp Clasico winner against Real Madrid.

Thankfully the end does not seem to be in sight just yet, though, and we can continue to watch on in awe at a player who may never be surpassed.