Next up for Puig is American Alison Riske, who needed three sets to subdue Ukrainian qualifier Kateryna Kozlova 4-6, 6-3, 6-3.

Another top flight player out of action is world No 13 Madison Keys of the United States, who announced on Twitter this morning that she was withdrawing from the tournament due to a foot injury.

That meant that Camila Giorgi took on Swedish lucky loser Rebecca Petterson in the round of 64, and she ended up taking an early exit herself after dropping the first set 6-2. Next up for Petterson is world No. 22 Croatian Petra Martic, who cruised to a straight-set 6-2, 6-2 win over Kristina Mladenovic of France Monday.

In the day session on court one saw Chinese world No 48 Wang Yafan outlast American qualifier Lauren Davis, who retired in the deciding third set after the pair split the first two 4-6, 6-4. Wang will face another American, Sloane Stephens, in the second round.

In other action on side courts in the day session, an all-Russian derby between qualifier Veronika Kudermetova and Ekaterina Alexandrova and took three sets to decide: 5-7, 6-3, 6-2 in Kudermetova's favor. She next faces world No 10 Belinda Bencic of Switzerland, who received a bye into round two.

Another qualifier, Christina McHale of the United States, came back from a set down to upset Latvian No 14 Anastasija Sevastova 4-6, 6-3, 6-3. McHale next faces Daria Yastremska of Ukraine in round two.

Australian Samantha Stosur managed to force a decider but was unable to overcome American world No 29 Amanda Anisimova, who won 6-3, 3-6, 6-3 in just under two hours. Anisimova next faces world No 2 Karolina Pliskova, who received a bye into round 2.

In the evening session on court one, world No 17 Sofia Kenin of the United States took down Anastasia Pavlyuchenkova in straight sets, 6-2, 7-6 (5). Next up for Kenin is Kenin Elise Mertens of Belgium, who logged a straight-set 6-4, 6-0 victory over Katerina Sinikova of the Czech Republic earlier in the day.

Next on court one, Czech Marie Bouzkova took out Slovenian lucky loser Tamera Zidansek in straight sets, 6-1, 6-3. Next up for Bouzkova is home favorite and current world No 16 Wang Qiang, who received a bye into round two.

In the evening session on center court, home hopeful Peng Shuai was beaten handily by Spaniard Garbine Muguruza in straight sets, 6-3, 6-2 in one hour 10 minutes. Muguruza fired off seven aces, converting each one of her break points and saving all that she faced. She will go on to play world No 3 Elina Svitolina of Ukraine, who received a bye into round 2.

The late games on center court saw round of 32 action get underway, with 5th-seeded Petra Kvitova defeating Polona Hercog of Slovenia 7-6 (6), 6-3. It was a battle of attrition in the first set, with both players holding serve to 6-all, taking the set to a tiebreak that Hercog was able to serve for but not seal the deal, smashing her racking in frustration and receiving a warning from the chair.

And the night wrapped up with defending champion Arnya Sabalenka clinically tearing apart American Danielle Collins from the baseline, winning 16 of her 22 first service points and firing seven aces on the way to an easy 6-1, 6-0 rout.