Xavi was left frustrated after his first game as Al-Sadd coach ended with a 1-1 AFC Champions League draw against Al-Duhail, in which he lost a shoe when kicking out in anger.
Barcelona great Xavi signed up to be the Qatari club's coach in May and his managerial debut came in Tuesday's last 16 first-leg clash with domestic rivals Al-Duhail.
The 39-year-old's coaching career got off to something of a rocky start, with Xavi at one point losing a shoe when he kicked out in frustration after his side were denied a penalty in the closing stages.
Xavi was ushered back to the bench by the officials while still wearing just one shoe, and the former Spain midfielder acknowledged his disappointment at the result and the referee's failure to award the spot-kick.
"My only disappointment is that we didn't win. It's not a bad result as we scored an away goal, but we deserve more than that. What makes me happy is how the players performed on the pitch," Xavi told his club's official website.
"It feels really good to coach this team. Our players were the best and had a great desire to win. The AFC Champions League is a tough tournament.
"Mistakes are part of the game. I don't like to talk about refereeing. A penalty call in the last minute of the game is tough for the referee, but in my opinion, it was a penalty."
With the Qatar Stars League not due to start until August 21, Al-Sadd's next fixture is the return leg against Al-Duhail on Tuesday, before they face the same opponent in the Sheikh Jassim Cup.