The fixture, whose winner was to earn a ticket to participate in the FKF Premier League this season, was called off in the 66th minute after United were awarded a contentious penalty by match referee John Sulwe.
Sharks contest penalty
A ball from the corner saw a United player go down under challenge inside the area and the referee pointed to the spot.
However, the referee's decision was immediately contested by Sharks players.
The players attacked referee Sulwe, prompting their fans to flood the field while baying for the referee’s blood. The referee was assaulted which being chased around the field before he was taken to safety by the security in charge.
By the time of abandonment, Sharks were leading 2-1. The first leg in Mombasa had seen United win 2-1 at Mbaraki Sports Club.
In Nairobi, United were the first to score when Christian Lubulu hit the back of the net in the sixth minute, but Sharks levelled matters in the 28th minute courtesy of Patillah Omoto.
Sharks then went 2-1 up in the 45th minute when Douglas Omanga finished off a cross from Omoto.
All eyes will now be on the Football Kenya Federation (FKF) Disciplinary Committee to see what decision they will take.
‘I believe in fair play’
Ahead of the game, Gor Mahia official Sally Bolo had questioned the decision by FKF to appoint Sulwe and his assistant Jane Cherono to officiate in the decisive return leg.
“I’m not questioning the integrity of any official personally, but as a football stakeholder, I cannot ignore what naturally raises questions,” said Bolo in a statement seen by Flashscore.
“For the FKF Premier League/NSL promotion playoff return leg between Sharks and Mombasa United, centre referee John (Sulwe) has been appointed after officiating only five matches cumulatively over the last two seasons. Assistant referee Jane Cherono is also returning after serving a suspension in the FKF Premier League before being demoted to the NSL.
“With so much at stake, appointments matter. They must not only be fair; they must also be transparent and inspire confidence.”
Bolo added: “I say this because we don’t want to leave our offices, travel to the stadium and sit through a match whose outcome football fans already believe has been determined.
“That is not good for the game, the clubs, the officials or the Federation. FKF has the administrative mandate to make appointments, but stakeholders equally have a legitimate right to ask questions when decisions appear questionable.
“I believe in fair play; not just for the 90 minutes, but in every process leading to those 90 minutes. Let the game be decided on the pitch, not by perception before kick-off.
“Transparency builds trust. Fair play must be seen, but it must also be believed.”
Sharks are fighting to keep their status in the top-flight while United are seeking to play in the league for the first time in their history.
FKF have already planned the new season to kick off on Friday with Nairobi United taking on KCB in the opener.