BARCELONA－Watch out Real Madrid.

Barcelona can still outscore opponents even on a rare day when Lionel Messi is far from his brilliant self.

Barca warmed up for Saturday's "Clasico" match at Madrid by routing Deportivo La Coruna 4-0 on Sunday to increase its lead at the top of La Liga.

Messi tried to join in the demolition, but the Argentina forward had a penalty saved by goalkeeper Ruben Martinez after he had already been frustrated on three separate occasions when he hit the woodwork. Jordi Alba and Luis Suarez also sent shots off the post.

Barcelona didn't need any goals from Messi, however, as Suarez and Paulinho both scored twice to help the Catalans capitalize on Valencia's loss at Eibar on Saturday.

"If we had practiced to hit the woodwork we probably wouldn't do it as well," Barcelona coach Ernesto Valverde joked. "Once the first goal fell, our opponent had to take risks and that made things easier."

Unbeaten Barcelona extended its advantage to six points over second-place Atletico Madrid, which jumped ahead of Valencia by beating Alaves on Saturday. Valencia is eight points behind Barca.

Real Madrid is 11 points adrift in fourth with a game in hand before this weekend's visit of Barca.

"We are pleased because the best way to prepare for a big match is to get a win beforehand and get that extra boost of confidence," Valverde said. "But nobody wins the league at this point in the season."

Martinez turned back a flurry of three strikes moments before Barcelona got going when Andres Iniesta caught Deportivo off guard as they tried to clear a corner. Iniesta picked out Messi with a lobbed pass before the Argentine controlled on his chest and teed up Suarez to score in the 29th minute.

Suarez got his second two minutes after the interval, driving home Sergi Roberto's superb curling cross at the far post.

Having only scored three times in his first 11 games this term, Uruguayan star Suarez now has six goals in his last five league matches.

Former Guangzhou Evergrande midfielder Paulinho doubled the lead in the 41st minute after a Messi shot came back off the post. Paulinho then bagged Barca's fourth goal in the 75th－again after following up a strike that hit the woodwork, this time from Alba.

The goals were Paulinho's fifth and sixth since the Brazil midfielder arrived in Spain from the Chinese Super League in the summer.

"Our rival was superior to us in every way," said Deportivo manager Cristobol Parralo.

Barcelona lost forward Paco Alcacer to a left leg muscle injury early on. The club said that he will be sidelined for three weeks, ruling him out of the Madrid match.

Despite his off day, Messi still leads the league's scoring chart with 14 goals.

La Liga's lack of goal-line technology or a video assistant referee (VAR) came under the spotlight again near the end of the first half when an audacious close-range 'rabona' effort from Suarez appeared to cross the line before Martinez punched it away.

It was a case of deja vu for the Catalans, who were also denied a goal three weeks ago when a Messi strike clearly crossed the line in a 1-1 draw with Valencia.