The Dutch scored a stoppage-time equaliser to force extra time, but the wily Croats, who finished third at last year's World Cup, scored twice in the extra 30 minutes to set up a decider against Italy or Spain.
The former Everton and Netherlands coach refused to answer a question about his relationship with Laporta, simply saying: "I am still here."
Barcelona President Joan Laporta backed Koeman last week but said the board would not shirk tough decisions if they needed to be made.
Ronald Koeman's Barca beat Real Sociedad 4-2 last weekend despite the shock of seeing Messi leave for Paris Saint-Germain.
Koeman said on Saturday that he was "excited about the team" and urged them to avoid "living in the past" ahead of the first Liga match.
The former Barcelona captain has always been a strong candidate for the job but he rejected to fill the position at Barcelona twice.
The Spanish Football Federation on Friday banned him for two games after the Dutchman was sent off during his team's 2-1 defeat at Granada.
Barcelona aim to get the three points and keep chasing the leaders, Atletico Madrid, who are topping the table with 4 clear points.
Koeman praised his side for their never-say-die attitude after they reached the Copa del Rey final with a 3-0 win after extra-time over Sevilla.
Koeman and his players are expecting a tough night in Bilbao when they face the city’s giants, Athletic Bilbao.
Messi returned to Barcelona’s squad for the match against Huesca after missing the team’s draw with Eibar last week.
Koeman said his side would find it difficult to win the La Liga title after they ended a traumatic 2020 with a 1-1 draw at home to minnows Eibar on Tuesday.
Coutinho is set to undergo knee surgery after sustaining an injury during Tuesday’s 1-1 draw with Eibar, the Spanish club said on Wednesday.
Koeman has called Valencia a difficult club to manage as he prepares to face his former team for the first time.
Lionel Messi scored his team’s winning goal over Levante after 75 minutes to save Barcelona from another negative result.
Barcelona out-classed Ferencvaros and eased their way to a 3-0 away win on Wednesday for a fifth consecutive Champions League victory.
Font believes luring former midfield great Xavi Hernandez back to the club would spark another golden age for the Catalans.
Messi came off the bench to score twice and lead Barcelona to a 5-2 home victory over Real Betis on Saturday.
Koeman cursed his side’s profligacy after they drew 1-1 at Alaves on Saturday, dropping points for the fourth game in a row in La Liga.
Neto made an embarrassing gaffe as his side were held to a 1-1 draw away to Alaves on Saturday, despite playing the final half an hour with an extra man.