Spain coach Vicente del Bosque labelled whistles at Gerard Pique "unfortunate" after the Barcelona defender received a mixed reception in Oviedo.

Pique was the target for some fans during Spain's 2-0 Euro 2016 qualifying victory over Slovakia on Saturday, with the 28-year-old's reputation having taken a hit following his rant at an assistant referee in the Supercopa de Espana.

While other sections of the stadium deliberately cheered the centre-back in an attempt to drown out the whistles, Del Bosque confirmed he had heard the taunting.

"I find it unfortunate that there are people that whistles a player of the national team," the coach said at his post-match news conference.

"The performance of the public in Oviedo has been fantastic these days. Gerard has played fantastically good football today."

Pique received a four-match ban in August for allegedly telling a match official "I s*** on your whore mother" during the Supercopa second leg against Athletic Bilbao.

Spain's victory took them to the top of Group C in qualifying for next year's European Championships, with first-half goals from Jordi Alba and Andres Iniesta putting the home side in control in the opening 30 minutes.

Del Bosque underlined the importance of Alba's fifth-minute opener.

"We were worried about Slovakia's game plan," the 64-year-old said.

"They don't give you any room to play in and they put a lot of bodies behind the ball, but we managed to break them down with the Jordi Alba goal, which came from a great move, and that helped us.

"They dropped back and we managed to play quite comfortably. We played really well."

Alba was similarly impressed by Spain's rapid start.

"It's been a while since we started so well," the full-back said.

"Lately we've played well in some games and not so well in others, but we played 90 fantastic minutes today and, in addition to how well we played, our intensity stood out."

Spain travel to Macedonia for their next qualifier on Tuesday.