Klinsman Omulanga scored at the death to secure a 1-1 draw.
"The first goal will give us a huge advantage," said Kimani.
The game lived up to expectations but ultimately it was a tale of missed chances.
Assistant coach Salim Ali took charge of the first session of preseason training.
It will be the first time Mathare United will be facing a coastal club on match day one.
Nyakeya equalised from the spot with only a minute left to play.
Juma returns from suspension to replace Omurwa who drops to the bench.
Mathare United will be chasing a top four finish against Gor Mahia on Wednesday.
Chris Ochieng' scored the lone goal to secure the away win.