Messi & Neymar: Barca's top duo or clash of egos?

There are three reasons why Barcelona is favored to keep its Spanish league title. They are as concise as they are convincing: Lionel Messi, Andres Iniesta and Neymar.

Known for its passing, Barcelona can now field three of soccer's most confounding and creative dribblers in the same starting 11 after Neymar joined the champions this offseason for $76 million, the eighth most expensive transfer in history.

Looks perfect on paper. So what could go wrong?

The soft-spoken Iniesta has always been happy to relinquish the leading role to Messi. But will Neymar, the bright and shining star of Brazil, be able to do likewise after being idolized as the next coming of Pele at Santos?

The 21-year-old Neymar insisted repeatedly the day of his introduction that he had ''come to add my part so that Lionel Messi continues to be the best player in the world.''

Weeks later, after his first game in Barcelona's burgundy and blue, he repeated his mantra of being happy in a secondary role.

''(Messi) is a marvelous person. We talk every day. There won't be any problems,'' Neymar said. ''The atmosphere on the team is better than I even hoped for. I knew that they were good, but when I arrived here I realized they were much better than I had thought.''

''I'm fulfilling a dream of my childhood by playing beside Messi, Xavi (Hernandez), Iniesta, (Carles) Puyol,'' he added. ''I'm trying to adapt as quickly as I can.''

Yet Neymar, who Pele said could surpass the almighty Messi one day, will have to learn Barcelona's style, which until now has let only Messi and Iniesta freelance one-on-one against backpedaling defenders.

And if Neymar does stay true to his word, Messi will still need to share enough of the ball - and shots - with Neymar to let him reach his full potential.

Messi is the engine of the Barcelona juggernaut that won 14 of 19 possible titles under Pep Guardiola from 2008-12 and then tied a Spanish-league record of 100 points en route to the title last season under Tito Vilanova.

Messi turned 26 in June and already is Barcelona's all-time goal scorer. Last season, he scored 46 goals in the league and was well on pace to break his own record of 50 goals from the previous campaign when he injured his right hamstring.

The four-time world player of the year has outlasted a list of strike partners including Samuel Eto'o, Zlatan Ibrahimovic and now David Villa, with whom he openly argued on the field before the Spain striker was sold this summer to Atletico Madrid.

Neymar, however, is different.

For the first time since Messi became its centerpiece, Barcelona has brought in a player who could represent its future in a distant post-Messi era.

For that reason, the two standouts will need to understand one another. Otherwise, it could be a real problem for Barcelona after it invested major money in bringing the two together with Iniesta, Xavi and Cesc Fabregas.

The task of making sure the two stars - one firmly established as among the best in history, the other striving to join him - get along will ultimately fall to new coach Gerardo Martino. The Argentine replaced Vilanova after Guardiola's former assistant unexpectedly stepped down in late July to focus on treatment for his recurrent throat cancer.

''I can't imagine (Messi and Neymar) not being able to play together,'' Martino said at his presentation. ''And if they can't play together it won't be their fault but rather a defect of the coach.''

The bottom line: If Martino can keep Messi and Neymar happy - and that means piling up impressive goal numbers - then the rest of the league should beware.