The Spaniard is delighted to have started the clash and warns against complacency for the return leg, while adding that he is pleased with the imminent arrival of the Arsenal man
The 20-year-old was given the nod to start for the Spanish and European champions at the Santiago Bernabeu as Sergio Busquets and Xavi had to sit on the bench after failing to fully recover from minor knocks.
Thiago, who impressed for Barca during the pre-season, did not hide his enthusiasm at being given the opportunity to be a starter against the Catalan giants' arch-rivals.
"I did not expect to be a starter and it was a surprise to be able to play because there were players like Xavi and Iniesta," he told reporters after the match. "I am very happy."
Despite Barcelona holding a slight advantage for the second leg at Camp Nou following a 2-2 draw in Madrid, Thiago insisted that they are taking nothing for granted.
"I believe there are no favourites, this is a two-legged tie and we did our part," stated the midfielder. "There are 90 minutes remaining."
Questioned about Barcelona finally confirming the signing of Cesc Fabregas from Arsenal, Thiago said: "He [Fabregas] is welcome.
"This team is always trying to reinforce itself with the best players for all positions and he is a player who will bring a lot."