Real Madrid midfielder Isco has admitted that January will provide a tough test for the Club World Cup holders.
Los Blancos, who currently lead La Liga, return to league action against Valencia this weekend, before facing Atletico Madrid in a two-legged Copa del Rey last-16 tie.
Real Madrid are currently on a 22-match winning run in all competitions, but Isco believes that run will be firmly tested in the coming weeks.
"It will be a very difficult start to 2015 for us. We are still confident ahead of January and hopefully we can produce the same form and go beyond 22 wins," the Spaniard told reporters.
Real Madrid face AC Milan in a friendly in Dubai on Tuesday.