Grinter was a strong opponent though, and brought a very strong service game with him. The pair shared the first two sets - Grinter winning the first in a tie breaker 7-6 while Tamai took out the second set 7-5.
The third set took the match well into the third hour but Grinter finally took it 6-4.
The No2 singles had Rotorua's Sean Martin playing against Nick Hammond.
After some resistance in the first set, which Martin took out 6-4, Martin went on to take the second set 6-1.
Rotorua's James Wilce played Jack Portegys in the No3 singles. Wilce's strong backhand allowed him to take that match 7-5, 6-3.
Rotorua's Jessie Galvin-Dawson was too strong for Cambridge's Mark Hammond winning that match 6-1, 6-2.
In the doubles rounds, Tamai paired up with Martin to face Grinter and Portegys in a match that proved to be a win for the Rotorua pair who took it in straight sets 6-4, 6-4.
The second doubles match had the Rotorua pairing of Wilce and Lionel Rogers up against Mark and Nick Hammond. Though this match proved to be a real battle, the Rotorua pair took that out in straight sets as well 7-5, 7-5.
The next round of the men's interclub competition includes a blockbuster match, with Rotorua hosting contenders Whakatane. That match will be played in a fortnight.
The Rotorua men's tennis team is made up of players from the Rotorua and Lynmore tennis clubs.