Messi was a surprise absentee from the starting lineup, along with Sergio Busquets, but he and the Spain midfielder were both called into action in the second half after Oscar de Marcos had put the visitor ahead.
The Argentinian hit the woodwork for the seventh time this season as Barca desperately chased an equalizer following its 2-1 defeat at lowly Leganes on Wednesday and 2-2 draw with Girona last weekend, eventually providing the cross for Munir El Haddadi’s 84th-minute leveler.
“We are not anxious because the season is long and has only just started, but we are angry about the last results,” Messi told reporters. “We didn’t expect them.
“Against Leganes we played well in the first half and lost, and today we created chances to win but couldn’t.”
De Marcos’s volley was the eighth goal the La Liga champion has conceded in seven games this season and Messi said his side urgently needed to improve in defense.
“We are aware that we have to be much stronger defensively,” added Messi, who inherited the Barca captaincy from the departed Andres Iniesta this season.
“Last year we hardly conceded goals but now teams are scoring against us with their first attempt. We cannot afford to concede goals in every game.
“We have to improve and become stronger in defense, which is the most important thing.”
Messi’s strike partner, Luis Suarez, also criticized the team’s display and said they needed to rid themselves of their dependence on their all-time top scorer.
“He is the best in the world but we can’t rely on Leo to always sort everything out for us,” Suarez said.
“The other players here are here on our own merits and we can’t depend on him or Busquets, we should have been winning when they came on to the pitch.”
The Argentinian, asked about Suarez’s comments, said he agreed with his teammate.
“We have the squad and the players to be a great team and not depend on anyone, like it always used to be at Barca,” Messi added.