Arsenal completed the signing of Xhaka from Borussia Monchengladbach for an undisclosed fee, rumoured to be worth £30million, on Wednesday.
The 23-year-old Switzerland international starred in Bundesliga, making 141 appearances for Gladbach after arriving from Basel in 2012.
And ex-Arsenal defender Djourou - now playing for Hamburg in Germany - likened his countryman to two-time Champions League winner and 2006 World Cup victor Pirlo, who plies his trade with New York City in MLS.
"Granit is a great ball player," Djourou told the Mirror. "The guy has a magical left foot. He can ping the ball all over the place. He is a strong tackler - he is very hard going into tackles - and overall he is a very, very, very good player.
"He can see a pass. He can tackle, he can assist. I would say, if I am being honest, there is a little bit of a Pirlo about him, just in terms of the precision that he plays the ball with. Granit can play those types of ball.
"He can come and get the ball and ping it 40 yards onto your feet. He is that kind of player, but with more physicality to his game.
"It is hard to give a perfect description but I would say he has a bit of Pirlo about him."