NGL Ladies Cecil Leitch
Northampton will confirm their place in the semi-finals with victory at Cold Ashby on Saturday after collecting their fourth win in five Group A matches with a 5-2 home success against Daventry.
Early points from Helen Brownless, Anne Goodchild and Mary Morris set the base, before Diane Pickford and Jill Cousins wrapped up the Harlestone victory by taking the final two games.
Wellingborough made it back-to-back home victories in Group C with a comprehensive 6-1 success against Elton Furze.
Jacqueline Mudd, Liz Rees and Diane Dickinson took the first three points with ease, and although Elton Furze reduced the arrears, the hosts held their nerve in the remaining three games as they secured a trio of narrow wins.
Rushden recorded their first victory of the season at the fourth time of asking with a battling 4-3 home success against Staverton Park in Group D.
Yvonne Wilcox, Hannah Talbot, Ali Thornhill and Claire McIlroy bagged the all-important points for the hosts.