Cameroon manager Volter Finke has admitted that there were no excuses for his side's performance in the 1-0 defeat to Mexico on Friday.
Oribe Peralta scored the only goal of the game in the heavy rain as Mexico tasted victory in their Group A opener, and Finke revealed his disappointment after the final whistle.
"The conditions weren't an excuse for our performance," the German told reporters. "We had some problems through the middle of midfield in the first 20 minutes or so, but we eventually adapted.
"The second half we were better, but overall we're disappointed.
"Now we've got five days before our next match, which will already be decisive for our World Cup."
Cameroon take on Croatia on Wednesday night.