Barcelona coach Ronald Koeman believes that winning the King's Cup will be the fastest way to achieve a title this season, and he will push a strong line-up against Rayo Vallecano in the round of 16 on Wednesday to ensure his team's progress in the competition.

Barcelona are third in the Spanish league, 10 points behind leaders Atlético Madrid, which may make it difficult for the Blaugrana to catch up with the brilliant leaders this season, as Coman said himself, referring to the loss of the League title this season as well.

But it remains the only team among the top three still competing in the King's Cup after Real Madrid were knocked out by a third-division team last week, and Atletico bid farewell to the competition earlier this month.

Barcelona beat Cornia 2-0 after extra time last week, and after losing the Spanish Super Cup final to Athletic Bilbao, the Copa del Rey appears to be the fastest way to win a title this season.

The Catalan giants will meet Paris Saint-Germain in the Champions League round of 16.

"We want to fight to win every title, but we have to be realistic, given Atletico's advantage in the league and the level of its players. It will be difficult to win the league title," Koeman told a news conference on Tuesday.

"But we will continue to fight for the league title. The King's Cup gives us a quick way to win a title where we play fewer matches than the league and I hope my team wins," he added.

Koeman got a moral boost by returning Lionel Messi to the squad announced today, Tuesday, after he ended a two-match ban, but the coach did not reveal whether the captain would participate in the cup match.

"Messi has felt a little tired recently, but he's rested and seems to have regained his energy and fitness again," he said.

He added, "He is a player who is accustomed to winning titles and wants to play every match, so I will talk to him tomorrow, and then I will choose the (basic) line-up."