Lionel Messi converted a penalty in Barcelona's 4-0 thrashing of crosstown rival Espanyol .

Barcelona continued its record start with 17 wins and a draw to maintain its 16-point lead over third-place Madrid. The leaders opened up a 12-point advantage over second-place Atletico Madrid ahead of its game later at Mallorca.

Barcelona coach Tito Vilanova returned to the touchline for the first time since undergoing throat surgery to remove a second tumor in two years on Dec. 20.

Barcelona dominated Espanyol from the start at Camp Nou stadium and made quick work of the relegation-threatened side after Xavi Hernandez scored in the 10th from a pass by Iniesta.

Pedro Rodriguez then added two more goals, first volleying in a cross from Cesc Fabregas in the 15th before chipping in Sergio Busquets' perfectly weighted pass in the 27th.

Two minutes later, Messi scored from a spot kick after Fabregas had been fouled by goalkeeper Kiko Casillas in the area. The loss was Espanyol's first in five games under new coach Javier Aguirre.

Last season, Messi set a league record with 50 goals. He already has 27 before the season's midway point. Atletico striker Radamel Falcao is next with 17th, followed by Ronaldo's 16.