Cape Town: Spain midfielder Xabi Alonso suffered a sprained ankle in the European champions` 2-1 win over Chile on Friday and may not be fit for the last 16 clash against neighbours Portugal.
Alonso, who has been in solid form alongside Sergio Busquets as one of coach Vicente del Bosque`s two holding midfielders, went over on the ankle late in the first half and had to be replaced by Javi Martinez in the 73rd minute.
"I have a classic sprain in the foot," Alonso told reporters after the match at Pretoria`s Loftus Versfeld stadium that saw Spain qualify as Group H winners ahead of the Chileans.
"We`ll have to test it out over the next few days and see how it feels and if I can make the Portugal match," he added.
Victory over the Portuguese in Cape Town on Tuesday would set up a quarter-final against Paraguay or Japan and Del Bosque`s side, one of the pre-tournament favourites, could meet either Argentina, Mexico, England or Germany in the last four.
Del Bosque said after the win over Chile that he was concerned about Portugal`s team as a whole and not just forward Cristiano Ronaldo, adding he had been impressed by their performance in Friday`s 0-0 draw with Group G winners Brazil.
"No, I am concerned about Portugal," he said at a news conference when asked about Ronaldo, who plays with Spain internationals Iker Casillas, Alonso, Sergio Ramos, Raul Albiol and Alvaro Arbeloa at Real Madrid.
"We saw today (Friday) how they controlled the Brazilians," Del Bosque added.
"They were not prevented from playing their football and they counter-attacked. The fact that we got Portugal in the next round instead of Brazil is not a relief."