The 26-year-old joined the club from Rayo Vallecano for a fee of around £2million this summer after notching 17 times for the Primer Liga outfit last year.
"My debut in the Premier League was incredible," he told Sky Sports.
"I never believed I would score two goals in a big victory for Swansea. I am very happy and looking forward to my first home match.
"It's not easy to score goals in England and to get two in 50 minutes was sensational. This is the way I dreamt it would be in this adventure.
"I just want to stay focused from match to match now. It will be hard to score two goals in every game but I promise the fans I will give my best in every game.
"The coach congratulated us after the 5-0 win and it was a dream start to the season.
And the physical approach to the game in England is not something that fazes the former Celta Vigo attacker.
"The English style is different to Spain due to the importance on physicality in England," he added.
"But that does not bother me because I am used to being in combat with opposition defenders because that is my game."