To mark the end of an incredible 2018 season, we're counting down the Top 5 WTA tournament matches of the year.

Topping our list is the back-and-forth thriller between Simona Halep and Sloane Stephens that decided the Rogers Cup title - the second such final of the year for the pair, making their rivalry one of 2018's most essential.

Top 5 WTA Matches of 2018:
No.5: Kerber d. Safarova, Sydney

No.4: Bertens d. Halep, Cincinnati
No.3: Danilovic d. Potapova, Moscow International
No.2: Kvitova d. Wozniacki, Doha

WHAT HAPPENED: Ahead of the Rogers Cup final in August, there was a serious frisson of anticipation as several narratives collided. A reprise of the superb Roland Garros title match, it pitted two players against each other whose careers had been intertwined since their concurrent rise up the rankings in 2013: World No.1 Simona Halep, finally a Grand Slam champion after taking the Parisian tilt, against US Open winner Sloane Stephens, returning to the tournament where her spectacular comeback from injury had begun.

In living up to expectations, the two-hour, 41-minute marathon confirmed their rivalry as one of the most compelling in tennis right now. Their matches are tests of strategy, willpower and stamina: for both players, fleet of foot but capable of brilliant offence as well, the key is finding a balance between attack and patience; to sense the right moment, in both individual rallies and in scoreboard terms, to pull the trigger - or to dig in and refuse to miss.

Read the match report: Halep survives Stephens in grueling battle to win Montreal

Little would separate the pair in a back-and-forth opening set that, at one hour and 12 minutes, was a mini-epic of its own. The Romanian forged a 4-1 lead to start, but was forced to cling on by her fingertips to save four set points - one with a simply brilliant forehand angle - and retrieve a 0-4 tiebreak deficit before emerging on top.

Though the grueling nature of the first set had made it feel like a must-win, a battling Stephens would upend that narrative to dominate the second set - but ultimately, just as in the Roland Garros final, it was Halep who pulled away in the decider, displaying greater tactical acuity deep into the match to control rallies from both offensive and defensive positions while her opponent began to bail out with impatient striking too quickly.

WHAT THEY SAID: After competing in two high-profile epic finals within three months, both players were full of respect for each other - and for similar reasons. "Every time I play her, she makes me a better player," Stephens said during the trophy ceremony; Halep repaid the compliment almost exactly, describing her opponent as a "complex" player and declaring: "She makes me play better and better every time we meet each other." 

Afterwards, the American was disappointed, but saw the match as a positive overall. "Obviously upsetting that I didn't win," she admitted. "But I think I got better today. I got better than the last final we played. Yeah, it's disappointing, but I think this will help me moving forward, getting ready to go into Cincy and the US Open. Just going to kind of take it all in, realize I did a good job this week, and I can be proud of myself for that."

Halep, for her part, spoke about how winning a Grand Slam had eased her mentality on court. "I really started to enjoy more the time on court," she explained. "I'm more relaxed. I'm not thinking about the result any more. Maybe that's why I'm able to win matches." Refreshed following her Roland Garros victory, she described the match as "crazy good" - and discussed the intertwined physical and mental nature of the sport, saying that although the tougher battle had been the physical one, "the mental part helped me today to stay there and to fight."

WHAT IT MEANT: Tennis is a sport where "what have you done for me lately?" is a paramount question, even for those at the top - and both Halep and Stephens entered the US hard court swing facing pressure to perform following disappointing first-week exits at Wimbledon. Montreal functioned as an emphatic response. Stephens, who came into the tournament at a career high of World No.3, demonstrated that she was ready and willing to take on the task of defending her haul of points from the previous summer - and despite coming out on the losing end, the manner in which she competed helped to begin building a reputation this year as a fighter, as well as a supreme talent.

Ironically, though, the player who had won her first seven Tour finals lost her grip on that streak this year. Montreal would be the second of three consecutive runner-up plates, something that Stephens will seek to rectify next year.

Halep, who had finished 2017 as World No.1 despite winning only one title, had continued to hold it for the bulk of 2018 - and although her entry into the Grand Slam champions' circle in Paris had alleviated that criticism at last, success only gives rise to greater expectations. In Canada, she met them. During the Romanian's title run this week - which extended her win-loss record for the year to 42-7, and which would be immediately followed by a final in Cincinnati - she not only showcased superb tennis but played with the authority and self-belief befitting her status.

In terms of points, a third title of the year - only Petra Kvitova would win more - tightened Halep's stranglehold on the summit, and getting back into trophy-lifting ways so quickly after her maiden Slam would be crucial to being bestowed the 2018 Player of the Year award. And while the quality of their two finals transformed the Halep-Stephens rivalry into a must-watch this season - their seven previous encounters had all been routine straight-setters - the Romanian maintains the upper hand, having now won five in a row to extend her head-to-head lead to 7-2.