Hamilton and Thames, locked at 45 points each after seven rounds, played each other over the weekend and the battle went to the wire before Hamilton won 5-4 to take an outright lead in Waikato-Thames Valley interclub tennis.
The scores were level at 4-4 with only the women's doubles match to go.
Sandy Tritt, recently back from playing at the senior world championships in Croatia, showed her experience and excellent doubles strategy to lead the Hamilton pair to the deciding win.
Tritt and Nicola Blake beat Libby Bird and Charmaine McGuire 6-1 6-2.
That put Fairview Motors Hamilton into a clear lead on 55 points, with Thames now in second place on 49.
Earlier the men had split the men's doubles one apiece but then Hamilton picked up only one of the men's singles while winning the two women's singles matches.
In the top men's singles Jake McCartney (Thames) proved too consistent for Matt Johnson and bagged the top singles in straight sets 6-3 6-3. Thames' numbers two and three followed suit with solid performances while the experienced Grant Kyd managed to sneak the bottom singles for Hamilton in a tight second set, winning 6-2 7-5 against youngster Joshua Cave.
Despite the Hamilton women taking out the two singles, Nicola Blake (Hamilton) had a long contest against young Bird after losing the first set in a tie-breaker but taking the next two sets 6-4 6-1.
Tritt had an easier time of it against McGuire with a 6-1 6-1 win.
The young St Peters team that has been gaining momentum in the past few rounds, beating Hamilton last week, had another win on Saturday, beating Cambridge 5-4 with four of the matches going to three sets.
The top men's and women's matches were both close with Cambridge winning both of them but the momentum was swinging from one player to the other before Robbie Wilkinson defeated Jono Merchant in a turnaround from his loss to him in round three, and Nina Paripovich fought off an improving Sarah Knighton to take her match 6-4 7-5.
St Peters won both the men's doubles matches to clinch the tie but Cambridge secured an important point, taking the women's doubles in three sets 3-6 6-4 (10-5).
There was no third tie on Saturday following the withdrawal of Te Awamutu-Otorohanga from the competition because of injuries and players being unavailable for the last few rounds.
After this round Cambridge and St Peters are fighting for fourth place for the final playoffs on Friday, November 30. With two rounds to complete the round-robin format, the young St Peters team seem to have an edge.
There seems no doubt that the grand final will be between Hamilton and Thames.
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