It was a day for the world No. 1s in Cincinnati, and sadly the continuing controversy of the Stan Wawrinka/Nick Kyrgios affair.

The French Open champion opened the day’s slightly delayed play on Center Court against a spirited Borna Coric, and he soon found to his cost that being slow off the mark meant the young Croatian would waste no time in capitalizing. That Wawrinka fought back from losing the first set was not the story. He might have looked a little inhibited at the start of the match, but he soon warmed up. But his comments to UK’s Sky Sports TV sparked another round of inquisition regarding last week’s notorious comments, this time tinged with a level of poignancy that had been lost in the general vilification.

Despite seeking out and confronting the Australian in the locker room, and Kyrgios’ apology, it transpired there had been no private apology to the people concerned – and that the situation was not as clear-cut as it may seem.

Wawrinka said, “I was struggling today to be completely on the court and to fight the way I wanted and everything.  It’s been a tough day for some people, and it's always difficult to completely focus on the tennis court.”

More tellingly, when the English question portion of the press conference was over, he wanted to make sure that all the questions were done and dusted because the topic had to end here. “That's not just a few words,” said Wawrinka, “but with one sentence he can touch a lot and hurt a lot of people. No one really sees the consequences for the people involved. That's the main problem, and that's the big concern for myself.  That's why it's tough to deal with.”

Following right along was women’s defending champion Serena Williams, who faced a bit of a test against Tsvetana Pironkova. In her first match since losing to eventual Toronto champion Belinda Bencic, all eyes were understandably on the performance of the Williams elbow.

After the match, Serena assessed her performance, saying “I feel fit, which is a start.  She's really getting a lot of balls back, so I was just really trying to fight and stay in there. I think it could be a lot better.  It's not where I would want it ideally, but I'm going to have to fix that more mentally than anything. I think once I lock in there I will be okay.”

Things were maybe a little more entertaining between Novak Djokovic, chasing that elusive Cincinnati Masters title, as he tackled the unpredictable Benoit Paire. The crowd were in for a treat in a good-natured match that served as a pleasing counterpoint to the angst and continuing drama from the beginning of the day.

“It was a strange match all in all,” said Djokovic. “The instructions I got from the coach was expect the unexpected, and that was the case. A lot of drop shots. He's got a great backhand. He's got a good serve. You couldn't really predict what kind of shot comes your way:  a slow spin ball or fast flat?  I had to stay alert all the time.”

“Also. I wasn't playing my best. It's the first match in Cincinnati, which has different conditions than in Canada, so it took me time to really adjust. This wasn't a first‑round opponent I really wanted, but, again, it was a satisfying match, and hopefully I can do better tomorrow.”

Djokovic will have been relieved at any rate to have gotten his match out of the way before the rain put a sizeable dent in the evening’s schedule, along with thunder and pretty impressive lightning. The upshot was that the night schedule on Center Court started almost two and a half hours later than planned, and Grandstand was still dealing with the carry over from the day session as Sloane Stephens resumed to force and eventually win a three-setter.

With Andy Murray and Rafael Nadal still to get their campaigns underway, the schedule can ill afford much more bad weather at such a crucial stage in players’ preparations.