On a day when Simona Halep, Svetlana Kuznetsova and Venus Williams also won their third-round matches, Kerber did not have it all her own way against 61st-ranked American Shelby Rogers.
The German, however, proved too strong ultimately, breaking five times for a 6-4 7-5 win on the main stadium hardcourt at Crandon Park.
"It's always good to have close sets, especially when you win them at the end. They give you confidence that you can go out in your next match knowing you can win close matches because you've just done it a day ago,” Kerber told reporters.
"[When] you win the match, you're always happy about your performance."
British 10th seed Konta also moved on with a 6-4 6-0 win over Pauline Parmentier as she seeks to bounce back from disappointing tournament in Indian Wells.
"I'm happy to have come through that," Konta said after the match.
"Although the scoreline doesn't show it in the second set, I still had to work hard within every single point. I really tried hard not to take my foot off the gas and stay focused on what I wanted to achieve."
Eighth seed Madison Keys, in her second event since returning from wrist surgery, was the only seed to lose on Sunday, falling to 72nd-ranked Spaniard Lara Arruabarrena 7-5 7-5.
Third seed Halep took less than an hour to polish off qualifier Anett Kontaveit of Estonia 6-3 6-0 with an aggressive performance that left the Romanian very pleased.
"I think I played my best match of the year," Halep said. "I was confident, and knew what I had to do ... everything went pretty well for me tonight."
Russian seventh seed Kuznetsova, the runner-up last year, stayed on track for another tilt at the championship when she bested American qualifier Taylor Townsend 6-4 6-2.
A week after losing the Indian Wells final to compatriot Elena Vesnina, Kuznetsova’s stronger second serve proved the difference, as she was broken just once while breaking her opponent four times.
The next challenge for 2006 champion Kuznetsova will be 11th seed Venus Williams, a three-time Miami champion, who was far too good for Romanian qualifier Patricia Maria Tig 6-3 6-0.
Johanna Konta and Australian 14th seed Sam Stosur also won their third round matches.
Read the original article on Eurosport: Kerber, Konta win in third round at Miami Open