Super-sub Philippe Coutinho 'changed the dynamic' in Barcelona win - Luis Suarez

Luis Suarez lauded the impact of substitute Philippe Coutinho as Barcelona came from a goal down to beat Real Sociedad 2-1 at Anoeta on Saturday.

Aritz Elustondo gave the home side a first-half lead but efforts after the break from Suarez and Ousmane Dembele helped Barca make it four wins from four in La Liga this season.

However, it was the half-time introduction of Coutinho, as well as Sergio Busquets' arrival just before the hour mark, which made the difference.

"Philippe came on and did really well," Suarez told beIN Sports after the game. "He changed the dynamic of the game.

"I think these are the type of wins which make a difference over a season, the type of games which can decide La Liga."

It was the second time this season Coutinho has come off the bench to help swing proceedings in Barca's favour -- he was also introduced while the game was goalless in the opening day 3-0 win over Alaves.

But despite bringing Coutinho and Busquets on to great effect, coach Ernesto Valverde was still criticised for welcoming pressure in the final 15 minutes by replacing Dembele with Arturo Vidal.

"You're just going to ask me about that one change, not the other two?" Valverde said in his postgame news conference.

"There were 15 minutes left and [Real Sociedad] were catching us on the break. I brought Vidal on to strengthen the midfield.

"Usually you make a change, you win and you're the king. Today, I've made a change, we've still won the game, but here we are [talking about one substitution] ... can you imagine!?

"With one, two or three changes the same thing was going to happen at the end because the opponent is also playing the game and they're pushing [for an equaliser]."

After taking a 12th-minute lead, Real Sociedad did well to contain Barca in the opening 45 minutes but they would be left to lament the chances they missed when the game opened up in the second half.

Mikel Oyarzabal fired over before Marc-Andre ter Stegen made two brilliant saves from Theo Hernandez and Juanmi as the Basque side found space on the break before Suarez's equaliser.

"Marc, for me, is the best goalkeeper in the world and he's been proving that in the best team in the world," Suarez said. "His performance today, for me, is proof of that."

The win represents Barca's second in a row at Anoeta following a seven-game winless streak in San Sebastian in the league.

It was a far from convincing performance, though, with Ter Stegen vital as the La Liga champions rode their luck at times in the second period.

"I'm not very worried, a little, maybe, but only a very little," Valverde said when asked if he was concerned with his team's display. "There are things to improve, but La Real can counter-attack well against teams and you can't forget that they also have a good team.

"It's not easy to win here and we had to take more risks when we were behind. I'm not returning home worried, but we will try to correct our mistakes."