The world and European champions' 2-0 defeat of France in Saturday's Euro 2012 quarter-final prompted criticism in Italian and other media that they lack attacking ambition, while some neutral fans at the game in Donetsk whistled and booed the Spanish for failing to provide a more entertaining spectacle.
"That's their opinion and just as valid as any other," Alonso told a news conference at Spain's Polish training base as they prepare for Wednesday's last-four clash with Portugal back at the Donbass Arena.
"Whatever people say I don't think we are going to change," added the 30-year-old, who netted both goals against the French on his 100th international appearance.
"I am pretty sure that most of the fans are enjoying great football games and great football teams.
"I think that's great not just for the present but also for the future of this tournament."
Alonso, flanked by team-mate Cesc Fabregas, said Spain, Portugal and other two teams through to the semi-finals, Germany and Italy, were all sides that liked to keep the ball, control games and look to attack at every opportunity.
"The teams that are there deserve it," he said, adding that Spain did not have a specific plan to counter the threat of his Real Madrid team mate and Portuguese captain Cristiano Ronaldo.
"We always play with the same idea whoever the opponent. In this case, we will analyse Cristiano's game and there may be small adjustments but we will try to play as a team because that's the best way to stop a player."
Spain coach Vicente del Bosque has been alternating between starting with Fernando Torres leading the line or deploying midfielder Fabregas as a roving forward and foregoing a recognised striker.
Fabregas laughed when asked how he compared to his Barcelona team mate Lionel Messi, the Argentine World Player of the Year who plays in a similar roving role for their club.
"I would never compare myself with Leo, that would just be bonkers," said Fabregas, who has two goals in the tournament.
"I don't think people are expecting me to beat four players and smash it in the top corner like he does," added the 25-year-old former Arsenal captain.
"I play where the coach asks me and that's it. I like the position, I have the freedom to get forward and people know my ability to get into goal-scoring positions and I think that's what they are expecting of me."
Both players were in sombre mood following the news on Sunday that Real Betis defender Miquel Roque, who started out in Barca's youth ranks, had lost a battle with cancer aged 23.
The Spanish players were also deeply affected by the recent sudden death of former Sporting Gijon coach Manuel Preciado, who had agreed to take over at relegated Villarreal.
"If there were already many reasons for us to want to win this European Championship, the death of two such important figures in Spanish football is now an extra motivation," Fabregas said.
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