Belgrade - Portugal have one of the world's top players in Cristiano Ronaldo but Serbia are good enough to contain him in their Euro 2016 qualifier in Lisbon on Sunday, the Balkan nation's captain Branislav Ivanovic said.
Portugal are second in Group I with six points from three matches, one less than leaders Denmark who have played a game more, while the Serbians are fourth with one point from three games behind Albania who have four from three.
Chelsea right back Ivanovic also acknowledged Serbia needed to come away with something from the La Luz stadium in order to keep alive realistic hopes of reaching next year's tournament in France.
"This is a massive game for us and definitely the pivotal moment in the qualifiers because we expected to take more than just one point from our opening three games," Ivanovic told Serbian media on Friday.
"Ronaldo is one of the best players in the history of football and it's not easy to stop him.
"To be the best you have to prove your worth every day and in every game and that's what he does. Containing him will be a huge challenge for us but we have what it takes.
"Portugal are a great team but their home 1-0 home defeat against Albania has shown that they too are vulnerable."
The match will be a competitive debut for Serbia coach Radovan Curcic, who took over from Dick Advocaat in November after the Dutchman stepped down following a tame 3-1 home defeat by Denmark.
Curcic has recalled out-of-favour Roma forward Adem Ljajic, axed by both Advocaat and his predecessor Sinisa Mihajlovic, and named uncapped striker Petar Skuletic and midfielder Filip Kostic in his squad.