Barcelona star Lionel Messi scored all four goals in a 4-0 rout of Espanyol to bring up his half century in La Liga and take his total goals tally for the season to a record-breaking 72 on Saturday. In what was Pep Guardiola\'s last home match in charge at the Nou Camp, Messi made sure there was a happy ending to what was an emotional night for the home fans. Thousands had turned out with flags and banners paying tribute to Guardiola and what he has achieved for the club during his four-year spell in charge. Barcelona may have conceded their 2011 league title to arch-rivals Real Madrid last week, but three-time FIFA Ballon d\'Or winner Messi gave the Nou Camp a boost by pulling ahead of Cristiano Ronaldo in the race for the league\'s top scorer title. Ronaldo scored a goal in Real\'s last-gasp 2-1 win over Grenada, leaving the Portuguese international striker on 45 league goals, five behind Messi with one league match remaining. Messi is now the undisputed all-time top-scorer in the history of European football, having overtaken the previous record of 67 goals scored by German legend Gerd Mueller for Bayern Munich in a single season in the 1970s.