Balmacewen won the top half but lost the bottom half in taking an eight-sets-to-seven win after rubbers were even at 3-3.
The win helped keep the pressure on St Clair, which took over top place with a 5-1 win over bottom-placed Taieri, while OBHS Blue got the same score against North Otago, which stayed bottom-equal.
Paddy Ou and Henry Neas were convincing winners for Balmacewen over Ryan Eggers and Megan Rogers respectively, leaving Ou unbeaten in club play this season. He allowed Ryan Eggers only three games in the top single.
Nick Cutfield grabbed a vital set off Lachie Kenneally in losing 6-1, 7-6, 6-1 and it required a 7-6, 10-8 second and third-set comeback for Ou and Neas to beat Eggers and Gavin Mockford after losing the first 6-3 in the top double.
Rogers and Kenneally had a similar tussle, dropping the first 6-2 but going on to win the next two 7-6, 10-7.
In the feature match between St Clair and Taieri, Mitchell Sizemore and Carlos Reid were in hard-hitting aggressive moods, with a few more rallies ending in Sizemore’s favour in the 6-4, 6-3 win.
Jeff Elliotte and Tony Ryder were too strong for Phil Williams and Eli Newall but the promising Bailey Godkin got a bonus point for Taieri in the bottom single.
The return of Manawa Rakete-Shea was notable in the Otago Boys’ Blue win against a depleted North Otago. He and Thomas Chiang were dominant in the top order and Michael Chen kept his fine record intact.
The only success for North Otago came when Kade Wilson beat Henry Dickson 6-2, 6-3.
Points after five rounds: St Clair 29 points (4 ties), Balmacewen (5), OBHS Blue 20 (3), Anderson’s Bay 20 (4), OBHS White 17 (3), North Otago 13 (4), Taieri 13 (5). Note: OBHS Blue v OBHS White to be played in own time from an earlier round.