It was at Barcelona where Koeman made his name as a player, racking up over 260 appearances and 10 trophies with the Blaugrana.
Barca endured one of their toughest summers this year, but Koeman didn't think twice about leaving his post with the Netherlands to replace Quique Setien.
The unrest derived from Lionel Messi handing in an official transfer request to leave the club, but the Argentine maestro has since pledged to see out the final year of his contract.
Barjuan played with the 57-year-old at Barca, and when asked by Tribalfootball about his appointment, the former left-back said: "I believe that he began working with Van Gaal at Barça and, from then on, Koeman has grown in experience as a manager with other clubs and, finally, he is now ready to lead at Barça this time around."
And his reputation should hold him in good stead as manager, according to Sergi.
"At club level, he was the one who scored the famous Wembley goal (that won Barça their first ever Champions League trophy) and from then on he was an icon for the fans.
"Let's just hope that people have patience with him as a manager… because rushing things always brings problems in football."