Portuguese forward Ronaldo, who lost his World Player of the Year crown to current holder Messi, has now netted an incredible 10 goals in his last four league outings to take his tally for the season to 11.
After scoring four against Racing Santander last weekend following braces against Malaga and Deportivo La Coruna, he struck two late goals at Alicante-based Hercules to keep Real at the top of the standings with 23 points from nine matches.
Argentina forward Messi grabbed his sixth and seventh of the season, Spain striker David Villa scored twice and former Sevilla player Daniel Alves netted one as Barca kept the gap to Real to one point with a dominant home performance.
Valencia's poor run continued when they were held to a 1-1 draw at home by struggling Real Zaragoza earlier on Saturday.
Hercules stunned Barca 2-0 at the Nou Camp in September and looked poised to pull off a second major giant-killing of the season when they took a shock lead over Real in the third minute at their Jose Rico Perez stadium.
Former France striker David Trezeguet, who turned 33 in October, met a David Cortes centre and sent a superb header sailing past fellow World Cup-winner Iker Casillas.
FRUSTRATED WHISTLING
With an annual budget of around 40 million euros, Hercules have about a 10th of Real's resources but they were able to frustrate Jose Mourinho's expensively assembled side until seven minutes after half-time.
Juan Calatayud fumbled a long-range Ronaldo effort and Angel Di Maria fired the rebound into the roof of the net.
The home side looked like holding on for a deserved point until the 82nd minute when Marcelo drove in from the left wing and Ronaldo was on hand to sidefoot home the rebound from Karim Benzema's shot.
The Portuguese grabbed his second four minutes later when Benzema pulled the ball back and he drove it past Calatayud.
Real coach Mourinho, who moved to the Spanish club from Inter Milan at the end of last season, said he was annoyed his side had conceded the early goal.
"We were playing practically on our own in the second half," the Portuguese told a news conference.
"The most important thing was the three points that keep us in first place in the league for another week."
Barca came roaring out of the blocks at the Nou Camp in the late kickoff and Messi put the champions ahead in the fourth minute before Villa curled in a sublime second in the 24th.
Sevilla defender Abdoulay Konko was shown a second yellow card and dismissed shortly before half-time and Brazilian fullback Alves put Barca three ahead against his old club eight minutes into the second period.
Messi raced through and sent a precise low shot past stand-in keeper Javi Varas for Barca's fourth in the 64th and Villa wrapped things up with a carbon copy of Messi's second in the 90th.
Valencia had been the season's early pace-setters, sparking hopes of a g
