Rafa Nadal had to wait for his match and India's Yuki Bhambri saw his match get cancelled.
Here are the updates.
Djoker through, Wawrinka stunned
Serbian Novak Djokovic overcame Brazilian qualifier Rogerio Dutra Silva in straight sets.
He defeated Silva in a 6-3, 6-4, 6-4 win to progress into the 2nd round.
Former French Open champion Stan Wawrinka was shocked in a five-set thriller by Guillermo Garcia-Lopez.
Wawrinka lost 2-6, 6-3, 6-4, 6-7, 3-6.
World number one Rafa Nadal's match against Simone Bolelli was suspended due to rain.
Other crucial results in men's singles
There was win for 13th seed R Bautista Agut in a 5-set thriller against Denis Istomin. Agut prevailed 6-2, 6-7, 1-6, 6-4, 6-4. Seventh seed Dominic Thiem won his match against Ilya Ivashka 6-2, 6-4, 6-1.
Wins for Wozniacki, Kvitova in women's singles
Second seed and 2018 Australian Open winner Caroline Wozniacki beat American Danielle Collins 7-6, 6-1.
Eighth seed Petra Kvitova won her 1st round match after coming back from a set down to beat Veronica Cepede Royg 3-6, 6-1, 7-5.
Japan's in-form Naomi Osaka too prevailed after sealing her 1st round tie against Sofia Kenin 6-2 7-5.
Azarenka ousted, wins for Safarova and Pliskova
Former world number one Victoria Azarenka lost in an epic 5-7, 5-7 battle against Katerina Siniakova. There were victories for Lucie Safarova and Karolina Pliskova respectively. 13th seed Madison Keys beat Sachia Vickery 6-3 , 6-3.