Right-back - Dani Alves
The right-back slot has two worthy contenders in Dani Alves and Philipp Lahm. While Alves is one of the greatest full-backs the world has ever seen, Lahm is one of the most intelligent players ever. However, Alves' style of play suits Guardiola's system better. Hence the Brazilian gets the nod.
The high-flying Alves was signed from Sevilla in 2008 and the Brazilian soon became an inspiration for other full-backs around the world.
Also Read: 10 footballers with most trophies in club football
Alves possessed pace, an engine to run up and down the pitch, great technique and a world-class delivery to go along with his good defensive capabilities. He became a vital attacking component of Pep's Barcelona and developed a great understanding with Lionel Messi.
He completed a successful 8-year spell at Barcelona before joining Juventus last season. This summer, he has moved to Paris Saint-Germain. The 34-year-old has nine European medals, only one fewer than Paolo Maldini, who has 10.
Alves became one of the world's best in his position under Pep and rightfully makes the list.
Centre-back - Carles Puyol (C)
A majority of players in Guardiola's greatest XI are the best of their generation. It is no different with Carles Puyol, the first centre-back on the list.
The Spaniard was one of the rare one-club men in recent times. Despite not being the tallest, Puyol was strong in the air, had great positional sense and was a born leader.
Also Read: Top 10 defenders of all time
Puyol won three Champions League titles with Barcelona aside from the Euro 2008 and FIFA World Cup 2010 with Spain.
The now-retired centre-back played 593 official matches for the Catalan club and captains Guardiola's greatest XI.
Centre-back - Gerard Pique
Now, there is a clash between Gerard Pique and Jerome Boateng for the second centre-back slot. However, the Spaniard just about edges the German based on the success he has achieved and the quality he possesses.
Pique is a Barcelona youth product who moved to Manchester United in 2004. He returned to Spain in 2008 after winning the Champions League with Manchester United in the same year.
Also Read: Sportskeeda's top 10 ball-playing centre-backs at the moment
Pique rose to become one of the world's best under Pep and his ability with the ball made him one of the best ball-playing defenders of all time. His technique allows him to play up front whenever Barcelona are chasing games, which is a rarity even among top centre-backs.
The 4-time Champions League winner completes a Barcelona rout in the heart of the defence.
Left-back - David Alaba
David Alaba is one of the most gifted players to emerge from Austria. Although Jordi Alba, Eric Abidal and even Lahm make their case for the left back slot, no one comes close to Alaba.
The Austrian joined Bayern in 2008 and it did not take him long to become a permanent fixture in the first team.
Alaba can play in central midfield as well as on the wings but left-back is his preferred role. He is a key player for Austria and was their youngest ever debutant.
He has already won everything at the club level with Bayern and at 25 years of age, is going to accomplish much more.
Thus, Alaba is a natural choice for the left-back role in Pep's greatest XI.