By Iain Rogers
MADRID (Reuters) - Lionel Messi blew the La Liga title race wide open when the Argentina forward netted a hat-trick in a 4-3 comeback win for the champions at 10-man Real Madrid in an action-paced 'Clasico' on Sunday.
Chasing a fifth title in six years, defeat for Barca at Real's Bernabeu stadium in a match watched by millions around the world would have all-but killed off their challenge but they came out swinging and took a seventh-minute lead through playmaker Andres Iniesta.
Real, looking to restore their three-point lead at the top and undefeated in 31 matches in all competitions, were reeling but hit back with a Karim Benzema double before Messi's first of the night, a close-range snap shot through a crowd of players to make it 2-2 at the break.
Cristiano Ronaldo put Real ahead from the penalty spot 10 minutes into the second half after he was tripped by Dani Alves and the match turned when home captain Sergio Ramos was sent off for felling Neymar when he was through on goal in the 63rd.
Messi clipped home the resulting penalty to level at 3-3 and struck the winner from the spot six minutes from time after Iniesta was knocked to the ground in the area.
The Real players were furious about both penalty decisions but Barca played a courageous game as they had promised and dominated possession, particularly after Ramos was dismissed, and thoroughly deserved the victory.
With nine games left, Real have 70 points, level with city neighbors Atletico Madrid, who won 2-0 at bottom side Real Betis in the earlier kickoff, and one ahead of third-placed Barca.
"It was an emotional match," Barca fullback Jordi Alba said in an interview with Spanish television broadcaster Canal Plus.
"We started strongly and then fell behind but we reacted well and managed to get an important win," added the Spain international.
"The games that remain are like finals for Barcelona, Atletico and Real Madrid. This victory will give us a big morale boost."
Messi's treble meant the four-times World Player of the Year became the all-time top scorer in 'Clasicos' with 21 goals, surpassing Real great Alfredo Di Stefano who scored 18.
Still only 26, Messi has also moved into second on the list of record scorers in La Liga on 236 goals, ahead of former Real striker Hugo Sanchez on 234, and he is closing in on record marksman Telmo Zarra's mark of 251.
In Seville, Atletico initially struggled to create chances against a dogged Betis side, who are bottom but are not giving up their top-flight status without a fight, but seized the initiative when forward Braian Rodriguez earned a second yellow card for a handball in the 56th minute and was sent off.
Midfielder Gabi, who rarely scores but hit a long-range stunner in this month's 2-2 draw at home to Real, cracked the ball into the corner from distance two minutes later and Diego Costa added a second from Koke's neat headed layoff in the 64th, his 23rd La Liga goal of the campaign.
Atletico's fine season under coach Diego Simeone has left them in with a real chance of becoming the first team other than Real or Barca, the world's richest clubs by income, to win La Liga since Valencia 10 years ago.
If Atletico and Real finish the season level on points, Atletico will take the title as they have a better head-to-head record thanks to the 2-2 draw at the Calderon and a 1-0 win at the Bernabeu in September, the only home game Real have not won this term.
Likewise, Barca have a superior head-to-head over Real after they beat them 2-1 at the Nou Camp in October, the last time the Madrid club lost before Sunday.
(Editing by Ed Osmond)