BARCELONA — Lionel Messi netted two goals within 15 minutes of coming on as a substitute to give Barcelona a 4-2 comeback win over Real Betis Sunday and push his team to the brink of the Spanish league title. After his teammates had rallied back twice to level at 2-2, Messi went on in the 56th and four minutes later curled in a free kick to extend his record scoring streak to 21 straight league appearances. The Argentina forward struck again in the 71st by polishing off a superb passing combination with Andres Iniesta and fellow goalscorer Alexis Sanchez to reach the 60-goal mark in all competitions for the second straight season. Barcelona leads by 11 points with four rounds to go and would clinch its 22nd domestic crown if defending champion Real Madrid drops points against Malaga Wednesday. Messi has been hampered for the past month by a right hamstring injury. Since hurting his leg on April 2, the four-time world player of the year has missed four games — including Wednesday's stinging 3-0 loss to Bayern Munich that sealed its exit from the Champions League — and come off the bench in two more before Sunday's match. Like last week's game at Athletic Bilbao, Messi looked fit enough as he again tilted the match in Barcelona's favor. Messi's double gave took his league-leading goal tally to 46 for the season, and kept him on pace to beat his own record of 50 from the last campaign. Elsewhere Sunday, Real Zaragoza beat Rayo Vallecano 3-0 to escape the relegation zone, while Mallorca remained in last place after drawing 1-1 with Levante. Sevilla, meanwhile, rolled to a 3-0 victory over Espanyol to move into eighth place. Real president Perez appeals for unity Sniping comments between Jose Mourinho and members of the Real Madrid squad have caused president Florentino Perez to make a rare foray into the limelight to call for unity at the club during the season run-in. The nine-time European champion hosts Malaga in La Liga Wednesday, in a rearranged fixture due to their involvement in the May 17 King's Cup final against Atletico Madrid. Second-placed Real must win to make leader Barcelona wait to be crowned champion, as it trails Tito Vilanova's side by 11 points with four games left. Anything less than a victory would gift Barca a fourth league crown in five years without having to play. Speculation over Mourinho's future has gone into overdrive since Real was denied a place in the Champions League final by Borussia Dortmund last week. “We have two big challenges in front of us with the Euroleague (basketball) Final Four and the King's Cup final,” Perez told reporters Monday. – Agencies