Colombia forward Jackson Martinez has warned that his team must stay focused when they face Japan at the World Cup tonight.

The South Americans are already assured of a berth in the second round, though their place at the top of Group C is yet to be confirmed.

While claiming that the hot conditions in Cuiaba will benefit his side, Martinez is well aware that Japan are capable of causing an upset.

"I think the weather will play a key role, but what causes upsets in football is how well you play. So whether it is hot or cold it is important that we concentrate on our game plan applied by the coach," he is quoted as saying by Goal.com.

"Japan is a strong team physically. They are players that have been characterised by giving everything until the end, so we must focus on continuing the good work that we have done."

Martinez has scored eight goals in 27 appearances for Colombia.