A win there will see him face one of Klizan or Feliciano Lopez in the quarter-finals. He is now being coached by former Tennis player Carlos Moya having been trained by his uncle Toni Nadal for almost 27 years.
Djokovic's disappointing 2018 continued in a 6-2 1-6 6-3 loss to Martin Klizan, the 12-time major victor having been a late addition to the draw following a round-three loss to Thiem in Monte Carlo.
Klizan claimed the first set in just 32 minutes before Djokovic broke the Slovakian's serve twice to take the second.
"I felt pain in three different parts of my body while warming up, and wasn't able to perform to my best", he said. Nadal is going for his 11th Barcelona title this week and the top seed looked ominously comfortable against Carballes Baena.
But when it was over, the win extended his current Tour record of consecutive sets won on clay to 38.
Only Guillermo Coria (35) and Ilie Nastase (34) have ever topped 30 straight sets.
Although Djokovic lost to Dominic Thiem in his third match in Monte Carlo, the performance he put on with the first two wins over Dusan Lajovic and then Borna Coric there reminded many fans of the old Djokovic and had them hoping he would continue to capitalize and build on his success in the upcoming tournaments, sort of like Kei Nishikori in Monte Carlo.
World number five Grigor Dimitrov survived an almighty scare against outsider Malek Jaziri on Thursday to edge into the quarter-finals of the Barcelona Open by beating the Tunisian 7-5 3-6 7-6 (8) following a nail-biting tiebreak.
Spain's Rafael Nadal celebrates after winning against Spain's Guillermo Garcia-Lopez during their Barcelona Open ATP tournament tennis match in Barcelona on April 26, 2018.
There's no love lost between Rafael Nadal and his uncle Toni despite the two ending their coaching partnership a year ago.