Kerber, the 2019 Eastbourne runner-up, managed to recover her form at the London-based Grand Slam last season when the German prevailed over United States star Serena Williams in the final to lift the 2018 trophy, reports Efe news.
Regaining her form last year now has helped the fifth-ranked German player Kerber to top her countrywoman Maria, 65th-ranked, in straight sets 6-4, 6-3 on Tuesday, after an hour and 21 minutes of play.
The former world No.1 Kerber is the player with the most number of matches won over the three most recent editions at Wimbledon, now with 17 encounters and only two defeats in the past three years.
Next up in Wimbledon's second round, Kerber is to take on Lauren Davis of the United States, who defeated Ukraine's Kateryna Kozlova 6-3, 6-2.
At her first Grand Slam as the top-seeded player, Barty stamped her authority over Zheng, world No. 43, with a 6-4, 6-2 win after 76 minutes of play, claiming her fourth victory over the Chinese player in their head-to-head clashes.
Barty also managed to extend her singles winning streak since the 2019 Roland Garros to 13 matches, as she was crowned the champion of the clay court French Open Grand Slam and the grass-court Birmingham tournament.
The Australian player is set to play Alison Van Uytvanck in the second round after the Belgian battled for a 6-4, 4-6, 6-2 win over Russia's Svetlana Kuznetsova.
The 23-year-old Barty won the 2011 junior Grand Slam title at Wimbledon at the age of 15.
If the top-ranked Aussie is to win this year's edition, she will be the first player to win the Roland Garros-Wimbledon double since Martina Navratilova did so in 1984.
In other Wimbledon first-round action on Tuesday, Elise Mertens of Belgium made the second round after her easy 6-2, 6-0 win over Frenchwoman Fiona Ferro.
In the second round, Mertens will play Monica Niculescu of Romania, who earned a hard-fought 6-2, 2-6, 7-5 win over Germany's Andrea Petkovic.
( With inputs from IANS )