The two teams were competing in the first match of their British Basketball League play-off quarter-final, however the tip-off was delayed by almost an hour as traffic on the M5 held up the arrival of match officials.
A second delay then followed in the third quarter as Leicester's head coach, Rob Paternostro, was involved in an incident with one of the spectators.
A statement from the Leicester Riders read: "In the third quarter of tonight's game our Head Coach Rob Paternostro was attacked by a spectator at Plymouth Pavilions.
"We would like to thank the medical staff who attended to Rob for their swift response.
"Both Leicester Riders and Plymouth City Patriots strongly condemn the actions of the spectator. There is no place for this behaviour in our game.
"The matter is currently being investigated by the Police."
The Riders were able to deal with the distractions effectively as they went on to win the match 86-71.
A further statement from the Plymouth City Patriots shed more light on the incident. It read: "At our game against Leicester an individual threw some liquid over head coach Rob Paternostro in the third quarter.
"We totally condemn this behaviour as a club which saddens us greatly having built up such a family fanbase and atmosphere over the season.
"Our immediate focus when the incident happened was to ensure Rob was ok and find the identity of the individual involved. This is now with the police and we will ensure that this isolated incident is not repeated."
The second match between the two teams will take place on Sunday at the Morningside Arena in Leicester.