Chanting protestors interrupted Shahar Peer's second round match at the Auckland Classic on Wednesday before the Israeli advanced to the quarter-finals with a 6-1 6-0 victory over Slovakia's Magdalena Rybarikova.
Italian top seed Flavia Pennetta advanced to the final of the Auckland Classic after thumping doubles partner Francesca Schiavone 6-3, 6-0 in under an hour on Friday
Williams had little trouble against the 31-year-old German although the gusty breezes at Auckland Tennis Centre played havoc with her ball toss, especially when she was serving for the match at 5-3 in the second set.
The 23-times Grand Slam champion looked a completely different player from the person who smashed her way into the semi-finals of the doubles with Caroline Wozniacki on Wednesday but managed to do just enough to beat the 86th-ranked McHale.
Top seed Agnieszka Radwanska's title defence at the Sydney International lasted just 92 minutes when she was dumped out of the second round by Bethanie Mattek-Sands on Tuesday.
Nick Kyrgios clinched his maiden tour title on home soil in a big confidence boost ahead of the Australian Open, beating Ryan Harrison 6-4, 6-2 in the Brisbane International final.