Dellacqua, who reached the biggest quarterfinal of her career last week at the BNP Paribas Open, a Premier Mandatory event just like this one, held all eight of her service games - and fought off all four break points she faced during the match - to get past Stefanie Voegele in straight sets, 63 62.
This year has been quite the revival for Dellacqua, who went into the Australian season ranked No.142 and, after just two and a half months, is now at No.56. And with no WTA main draw match wins to defend for six months - she didn't get one last year until Tokyo in September - she could be well on her way to her best ever ranking, having originally set her career-high ranking of No.39 back in 2008.
Pironkova and Nara, who won their maiden WTA titles earlier this year at the Premier-level event in Sydney and the International-level event in Rio de Janeiro, respectively, won through in straight sets as well. Pironkova held off a late surge to beat Galina Voskoboeva, letting a 5-3 lead slip in the second set but eventually prevailing, 62 75, while Nara outlasted Annika Beck in a tight two-setter, 76(2) 64.
Elina Svitolina, who won her first WTA title last summer in Baku, was also among the winners, rallying from a break down in the third set to edge Bethanie Mattek-Sands in an hour and 53 minutes, 63 36 63.
"It was a tough match. It's always tough to play against someone playing at home," Svitolina said. "I think I was playing really aggressive today, and in the important moments I was staying pretty strong, mentally - I didn't break in the important moments. So I was really happy with how I played today."
"We've played three or four times, first in juniors and then a few times more recently," Svitolina said. "I remember all of them. She's a great player and I'm really looking forward to playing that match."
The qualies also wrapped up, with Shahar Peer, Virginie Razzano, Patricia Mayr-Achleitner, Kimiko Date-Krumm, Olga Govortsova, Katarzyna Piter, Estrella Cabeza Candela, Donna Vekic, Nadiya Kichenok, CoCo Vandeweghe, Zarina Diyas and Kiki Bertens all securing spots in the main draw.
Elsewhere on Tuesday the doubles draw was made, with Hsieh Su-Wei and Peng Shuai, Ekaterina Makarova and Elena Vesnina, Sara Errani and Roberta Vinci, and Kveta Peschke and Katarina Srebotnik the Top 4 seeds. Other teams to watch this fortnight are the wildcard pair of Martina Hingis and Sabine Lisicki and former US Open champions and co-No.1s Liezel Huber and Lisa Raymond.