It is now or never for Lionel Messi.  The Argentina superstar’s once-in-a-generation career will be defined — for many — by whether he leads his country to the World Cup title on Sunday.  Can he finally, at the age of 35, win football’s biggest prize to secure his place alongside Pelé and Diego Maradona in the pantheon of the game’s greatest ever players?  Standing in his way is France, the defending champion, and Kylian Mbappé, the player best positioned to take over from Messi and Cristiano Ronaldo as football’s marquee name.  That's if he hasn’t already.  Mbappé also is standing on the cusp of history heading into the match at the 80,000-seat Lusail Stadium, a title decider that is filled with storylines.  The 23-year-old France forward is looking to emulate Pelé by being a champion at his first two World Cups and set up the prospect of a third title, a feat only ever achieved by the Brazil great who has been hospitalized during this year’s tournament because of a respiratory infection.  Mbappé was 19 when he led France to its second World Cup title in 2018, becoming the youngest scorer in a final since a 17-year-old Pelé did so in 1958. While Pelé ended up being a peripheral figure in Brazil's 1962 triumph — he didn't play in the knockout stage because of injury — Mbappé has been France's go-to player in the team's bid to repeat.  Indeed, Mbappé enters the final tied as the tournament's leading scorer with five goals. The player alongside him? Messi, of course.  Who wins the Golden Boot — the award for the top scorer — is just one of the many other narratives around the final.  There's France, the dominant national team of this generation, looking to become the first to win back-to-back World Cups since Brazil in 1962. The country that produced Michel Platini, Zinedine Zidane, Thierry Henry and now Mbappé will be playing in the final for the fourth time in the last seven World Cups, more than anyone else.  Then there's Didier Deschamps, a World Cup winner as a player in 1998 and now bidding to win it two times as a coach. Vittorio Pozzo was the only other man to coach two world champion teams, with Italy in 1934 and 1938.  Like France, Argentina is seeking a third World Cup title — after 1978 and 1986 — to move into outright fourth place in the all-time list. It would end a 36-year wait for football’s biggest prize, since Maradona's string of virtuoso performances in Mexico in 1986.  That made Maradona forever a hero in Argentina, and an icon around the football world. Messi now appears to be at that level — win or lose on Sunday when he'll play in a record 26th World Cup match.  Messi has evoked comparisons with Maradona in the way he has pushed Argentina to the final, scoring five goals, setting up three more and thrilling his team's legion of fans, who have poured into Qatar throughout the World Cup in numbers only really matched by those from Morocco.  In that sense, it will seem like a home game for Argentina, with France's supporters sure to be heavily outnumbered amid a sea of blue-and-white jerseys — many of which will have “MESSI 10” written on them.  It is hard to pick a winner.  France is a hardened tournament team with plenty of experience and the quality to eke out wins when not playing at its best. Deschamps has kept France's level high despite losing key players ahead of the tournament like Paul Pogba, N'Golo Kante, Presnel Kimpembe and Karim Benzema, the reigning world player of the year.  The French are the masters of being pragmatic, defending compactly and breaking at pace, typically through Mbappé down the left and through Antoine Griezmann, reinvented over the past month as a midfield playmaker.  Indeed, expect to see Mbappé and Messi walking around a lot during the game, not bothering to defend or press. That is in the script, rather than them being lazy. Part of the skill of Deschamps and Argentina coach Lionel Scaloni is their ability to forge a team that has learned to defend a man light.  As for Argentina, the team is largely set up simply to get the best out of Messi, with Scaloni likely to select a quartet of central midfielders like in the 3-0 win over Croatia in the semifinals. They will scrap and press, and then give the ball to Messi to weave his magic. Or to Julián Álvarez, the striker who started the tournament as a backup for that unthinkable 2-1 opening loss to Saudi Arabia and now is undroppable with four goals to his name.  Álvarez is pinching himself that, at 22 and pretty much at the start of his career, he is the attacking foil for Messi at the great man's last World Cup.  Similarly, the tens of thousands of spectators inside the stadiums in Qatar, and the millions watching on television around the world, have continued to be amazed at the magic Messi keeps on delivering.  Anyone who isn’t French, or maybe a fervent fan of Ronaldo, is likely to be willing on Argentina's diminutive No. 10 in the biggest match of his career.  Eight years ago, Messi walked away from the 1-0 loss to Germany in the 2014 final with the Golden Ball award for the tournament’s best player.  This time, he'll want instead to be lifting another trophy, made of 18-carat solid gold, to cap a career like no other.