Pedro fired the away side into the lead after 33 minutes, but Rayo skipper Roberto Trashorras passed up the opportunity to level from the penalty spot in the latter stages of the first period.

Pedro scored his second in the early stages of the second half, before completing his hat-trick 20 minutes from time.

Barcelona were not finished, however, with Cesc Fabregas adding their fourth with a curling effort in the latter stages.

Here, Sports Mole dissects the 90 minutes of action between the two Spanish rivals.

Match statistics:

Rayo Vallecano:
Shots: 10
On target: 8
Possession: 54%
Corners: 5
Fouls: 21

Barcelona:
Shots: 11
On target: 8
Possession: 46%
Corners: 14
Fouls: 16

Was the result fair?

If the match had ended at half time, then a case could have been made for Rayo, who were in control for long periods. However, the second period was utterly dominated by Barcelona, who could have had five or six but for some slack finishing in the latter stages. The Catalan outfit are certainly setting the early pace in Spain's leading division.

Rayo Vallecano's performance

Rayo might have been left empty-handed this evening, but Paco Jemez would certainly have been pleased with the level of performance from his side, despite the fact that they conceded four goals. They could and perhaps should have taken the lead in the early stages with a number of opportunities, but they could not find the back of the net. Unfortunately, the match got away from them in the second half with Barcelona running riot.

Barcelona's performance

The away side struggled in the opening 30 minutes or so as Rayo put them under constant pressure, but they utterly dominated in the second period. They have and will play better this season, but they scored four times without reply, which is a scary thought for the rest of the league. The only surprise for the Catalan outfit is that they scored four times and Messi was not among them.

Sports Mole's man of the match

Pedro: The Spanish winger has had to share the wide right duties with Alexis Sanchez this season, but he staked his claim for a regular spot with three fine goals this evening. Rayo simply could not deal with his pace and intelligent running during the 75 minutes that he was on the field.

Biggest gaffe of the match

Trashorras had a golden opportunity to level for the home side in the latter stages of the first period after being brought down by Adriano inside the box. However, his lacklustre penalty was saved by Victor Valdes. It might not have effected the final result, but it would have given his side real hope.

Referee performance

Clos Gomez had a difficult first 45 minutes with the challenges flying in from both sides, but he did get the majority of the decisions correct - including the penalty award for the home side. He was perhaps too lenient with Adriano, however, who might have walked for a series of late challenges. He has hardly seen in the second period, which is always a good sign for a referee.

What next?

Rayo Vallecano: Rayo will attempt to pick up their second win of the season when they make the trip to Sevilla on Wednesday.

Barcelona: The Catalan outfit return to league action on Tuesday when they welcome Real Sociedad to Camp Nou.