The 2018 US Open will be remembered as one of the most dramatic grand slam tournaments in history.

It ended with the big titles going to Naomi Osaka and Novak Djokovic and took in all manner of controversies and talking points.

Here, Press Association Sport picks out five things we learned.

Clarity on the rules

Serena Williams, right, clashed with umpire Carlos Ramos, centre, in the final
Serena Williams, right, clashed with umpire Carlos Ramos, centre, in the final (Adam Hunger/AP)

Tennis umpires have arguably never been more high profile. After Mohamed Lahyani’s mid-match pep talk to Nick Kyrgios caused uproar, Carlos Ramos became the third player in the women’s final. In giving Serena Williams three code violations, the Portuguese official was applying the letter of the law, but other umpires would probably have given her a bit more leeway. As with referees in football, the frustration comes from a lack of consistency. Particularly with coaching from the stands, there is a tacit understanding that it goes on, but it is punished only sporadically. It is no surprise players feel they are being treated unfairly if not everyone is treated the same.

Feeling the heat

The extreme heat was an issue for players in New York
The extreme heat was an issue for players in New York (Frank Franklin II/AP)

Aside from the officiating, another major talking point has been how tennis handles extreme heat. Conditions in New York have been among the most punishing at any slam, with complaints from players about being put in danger and a lack of ventilation on Arthur Ashe Stadium. The WTA has a standard policy of allowing a 10-minute break between the second and third sets of matches, while the US Open introduced a similar one for men. The Australian Open has a limit where play is deemed unsafe, but the US Open decided such a policy was only necessary for junior and wheelchair players. With extreme conditions set to become more frequent, a common approach is needed.

Osaka on the up

When the furore over the events of the final and whether Williams was villain or victim dies down, it will hopefully be appreciated what a remarkable performance this was from Osaka. The 20-year-old has been a rising talent for several years, with her forehand known as a major weapon, but, under the guidance of Williams’ former hitting partner Sascha Bajin, Osaka has become a much more rounded player and someone able to handle the big occasion with ice-cool calm. Allied to her endearing, quirky personality, there is no doubt tennis has a major new star.

Djokovic on the prowl

It seems an eternity ago that questions were being asked about whether Djokovic would ever return to his best. After lifting the Wimbledon and now US Open crowns, the Serbian has tied Pete Sampras with 14 slam titles and only has Rafael Nadal (17) and Roger Federer (20) above him in the history of the men’s game. Both his rivals may well add more titles, of course, but Djokovic had been winning them at a much faster rate until his recent hiatus and getting into the 20s does not seem beyond the 31-year-old.

British tennis still needs Murray

Andy Murray’s second-round exit seems a long time ago and was his earliest at a slam for a decade. But there were enough positive signs to at least indicate the Scot could return to being a factor at the latter stages of slams again. And Britain is not ready for him to bow out just yet. While Johanna Konta and Kyle Edmund have both excelled in their own right, neither made it past the first round here, and no British singles player has made it into the second week at four of the last five slams.