Spain may summon its most experienced player for its most important match at the European Championship.

Sergio Busquets is set to return for the match against Slovakia on Wednesday, when “La Roja” faces the possibility of an embarrassing elimination in front of its fans.

Only victory for Spain will be enough to ensure a spot in the round of 16 at Euro 2020. A draw may be enough, but only if Poland doesn’t defeat Sweden in the other Group E match. Both games will be played at the same time.

The 32-year-old Busquets, the only player left from Spain’s World Cup-winning squad in 2010, didn’t play in the team’s first two matches after testing positive for the coronavirus. The Barcelona midfielder had to go into isolation and only rejoined the squad on Friday. He did not dress for the game against Poland on Saturday.

“I kept the motivation to keep training and to be in the best possible condition after having the virus,” Busquets said Tuesday. “It was a bit boring to train by myself but I knew it was what I had to do to be as prepared as possible.”

Spain coach Luis Enrique didn’t want to risk playing with Busquets in the second match but said he will be available on Saturday along with the rest of his teammates.

“We didn't want to risk it with such an important player as Busquets after he spent 12 days training in the garden of his house,” he said.

Rodri Hernández played in Busquets’ position in the first two matches, a 0-0 draw against Sweden and a 1-1 draw against Poland.

“We missed him,” Spain defender César Azpilicueta said. “We tried to make up for his absence, but Sergio is a key player for this team and we are happy that he is back.”

Slovakia coach Stefan Tarkovic said Busquets' return will be a big boost for Spain.

"(He will) bring higher quality and calmness in the middle of the pitch,” Tarkovic said. “It’ll be a challenge for us.”

Azpilicueta himself may be another veteran called upon to help the Spanish squad as it faces elimination. The 31-year-old Chelsea right back has yet to play at Euro 2020 as Luis Enrique preferred to use Marcos Llorente in the position.

Jordi Alba had taken over as captain in the absence of Busquets. The national team’s longtime captain, Sergio Ramos, was not called up after playing sparingly in the final part of the season with Real Madrid because of injuries. The decision to leave him out of the squad even though he would have been fit to play by the time Euro 2020 started drew a lot of criticism against Luis Enrique, with many saying the team was left without a true leader.

"It’s a young national team, but we have many important players with a lot of experience with their clubs and in big tournaments,” Busquets said.

Spain, playing all of its group matches in Seville, is two points behind leader Sweden and one behind Slovakia, which surprised with an opening 2-1 win over last-place Poland before losing to Sweden 1-0.

Slovakia needs a draw to guarantee its spot in the next round. It is making its second consecutive appearance after debuting at Euro 2016. Both Slovakia and Spain were eliminated in the round of 16 in 2016. Spain last missed the knockout round in 2004.

Slovakia hopes to stun Spain again like it did in 2014 by ending “La Roja’s” 36-match unbeaten run in qualifying for a European Championship or a World Cup.

“We shocked Spain seven years ago and I dream it happens again,” Slovakia captain Marek Hamsik said. “You never know in soccer.”

It remains unclear what kind of support Spain will receive from its fans at La Cartuja Stadium after a video of players ignoring fans at the team hotel last weekend was widely shared online. The crowd remained supportive when the team arrived at the hotel on Tuesday, when players were constantly waving as they passed by.

There is also uncertainty about the field conditions at La Cartuja, which prompted complaints by some players after the first two matches.

Busquets said he was experienced enough to know that there was no reason for Spain not to be hopeful on Saturday.

“I’ve had the luck of playing in many European Championships and World Cups and most of the time we arrived at the third match with the feeling that we deserved more," he said "but we always depended on ourselves and most of the time we advanced and won titles."