But the Argentine-born Pekerman lauded the "Cafeteros" (Coffee-makers) for holding their own after the expulsion and scoring an equalizer in the first half thanks to Juan Quintero's clever low free kick in the 39th minute.
But Japan were dominating possession and their pressure told when substitute Keisuke Honda's corner found Osako, who outjumped his marker and headed the ball into the far corner of the net, beyond Ospina's reach.
In third and final match of the day, World Cup hosts Russian Federation face an Egypt side in their second match of the World Cup, knowing a win will all but guarantee a place in the last 16.
The South Americans open their Group H campaign against Japan in Saransk on Tuesday after making their final preparations at a picturesque ski resort overlooking the Volga River.
- Japan are on their sixth World Cup appearance, having made their debut at the 1998 tournament in France.
However, the South Americans face a Japan side who would struggle to avoid an early World Cup exit even if they were under Jose Mourinho, according to former coach Philippe Troussier.
India wins toss, to bat vs Afghanistan in historic 1st test
Several Afghan one-day players like Rashid Khan and Mohammed Nabi have performed well in the IPL series in India . He hasn't played Test cricket so we need to look and see what happens.
You can see that game on Now TV's World Cup channels (618 and 619).
"We can not fall in the trap of feeling overconfident in this match", Colombia midfielder Abel Aguilar said.
If James is sidelined, Colombia, who are hoping to at least return to the quarterfinals after making it there for the first time in 2014, know that success in Russian Federation about more than just the presence of one player.
How do I watch online live streaming of the FIFA World Cup 2018 Colombia vs Japan match?
"We have enough players for replacement".
"Despite that, I think we will cope", said Japan captain Makoto Hasebe.
"Usually the first match is hard for every team and Colombia should be no exception", Japan defender Maya Yoshida said.