Forlan eyes 100th Uruguay cap against Nigeria
"We absolutely must win to have the chance of going further in the Cup," Forlan told reporters before the match against the African champions, who crushed tiny Tahiti 6-1 on Monday.
"They won the match they had to win, scored lots of goals and even a draw will be better for them than us," said the 34-year-old striker, who was named best player at the 2010 World Cup.
"Nigeria have good players, many play in Europe, they are physically strong, it won't be at all easy. It will be a hard match," added Forlan, who will also be looking to add to his Uruguay tally of 33 goals.
Copa America holders Uruguay lost 2-1 to world champions Spain in their Group B opener on Sunday with Forlan coming on as a 69th-minute substitute.
A draw could leave Uruguay needing a big-scoring win in their last match against Tahiti and a Spanish win over Nigeria on Sunday to stand any chance of a place in the semi-finals.