I'm going to remember 2018 as the tennis year when the past collided with the future, when Serena Williams tried to hold off newcomers such as Naomi Osaka. This has been an interesting year for the women's game, which has seen the emergence of new faces, new stars and new possibilities. 

Serena's comeback was huge. To make the finals of both Wimbledon and the US Open, after being away for a year to start a family, was an amazing feat. Unfortunately for Serena, the performance of the year was the match that Osaka played to win the US Open final, giving her her first (but certainly not her last) Grand Slam title. That final was for me also the most memorable match of the year. With all the drama and suspense in New York, and with everything that was going on during the points and also between the points, that match was one of a kind. We had never seen drama like that before and we will probably never see it again. 

Naomi Osaka (Getty)

Osaka is a star now, and she's only going to carry on getting bigger and bigger. But this year I have also seen the potential of some of the other young players coming up, women such as Daria Kasatkina, Aryna Sabalenka, and Elise Mertens. Kiki Bertens may be a little older, but she made a huge leap up this year as well.

We had five different winners of the five biggest tournaments - the four Grand Slams and the BNP Paribas WTA Finals Singapore presented by SC Global. Was that a good thing for the women's game? Well, yes and no. You have more parity and a deeper field, which is a good thing, but at the same time it's harder to develop rivalries and also superstars if you have so many different people winning things. 

LOOK: WTA Top 10 and their 2018 best results

You might say that we are now in a period of predictable unpredictability. We now almost expect unpredictable results, with the leading players experiencing so many ups and downs. The top players could lose in the first round or, if they survive that opening match, they could go on to win the whole thing. And that was even happening at the majors. I guess this lack of consistency is the new normal and we're going to keep on seeing it. It's interesting to watch - when the top women play well, they can play lights-out tennis, but then what happens to them at their next tournament? 

Caroline Wozniacki won her first major at the Australian Open and then had a fairly quiet rest of the year. We don't yet know how she is going to handle rheumatoid arthritis. This was also the year that Angelique Kerber won Wimbledon pretty much from nowhere. I'll also remember this year for Simona Halep's breakthrough at the French Open, where she won her first major, and for finishing the season as No. 1. We had Elina Svitolina winning her first big title at the WTA Finals, and I'm sure we're going to see more from her in 2019. 

At the same time, some of the players who did well in 2017 - such as Garbiñe Muguruza, Jelena Ostapenko and Venus Williams - had a quiet year, while Maria Sharapova wasn't a factor in 2018, and I wonder, if she doesn’t start winning a lot more, just how much longer she is going to keep playing. I must give a special shoutout to Petra Kvitova, who is bravely continuing her climb back up the rankings all the way to  No.7. Brava.

One theme I've picked up on 2018 was players using more variety and more parts of the court, with more drop shots and slices and forays to the net. I think that's the way the game is going, with people seeing how you can shape the ball, and all you can do with the ball, and the players are getting more imaginative with all the possibilities that spin opens up. These days, you need to bring more to the table than just hitting very nice forehands and backhands. Hitting hard groundstrokes isn't going to win you matches on a consistent basis, and it's certainly not going to win you majors. I also think bigger serving is coming our way, as is more athletic tennis. 

As I review 2018, I'm already starting to look ahead to 2019. I think it will be another fascinating year.