The Nigeria topflight log-leaders failed to widen the gap at the top after losing 1-0 to the Flying Antelopes in a Week 18 rescheduled encounter on Wednesday.
"We lost to Rangers not because they were a better team but we lost due to our own mistake," Boboye told Goal.
"We have to go back home and work on the mistakes we've picked up from this match.
"We had a couple of chances to level in the game, the closest being the one that hit the bar and from there I knew it may not be an easy one for us.
"I think Rangers aren't a bad team, they've been together for a while and if they continue with the way they played, then they will come out well in the second round," he concluded.
The Peace Boys remain top of the NPFL standings, one point ahead of MFM and El-Kanemi Warriors, who sit in second and third respectively.