Cristiano Ronaldo laid down the Ballon d’Or on the plinth in front of him and began his acceptance speech, Sepp Blatter to his left, Thierry Henry to the right. As he drew to a close he thanked everyone and then paused. He leant in towards the microphone, clenched his fists and boomed out a long, deep “Sí”. This was Ronaldo’s third Ballon d’Or but he was determined it would not be his last. Only one player has won more and he was sitting in the front row, a runner-up: Lionel Messi.

“This is the eighth time I have been here and it is always Messi and I and one other player,” Ronaldo said later. Before the presentation, the two footballers had met briefly. Ronaldo called Messi over to meet his son, telling the Argentinian that Ronaldo junior watched him on television, talked about him. He also admitted that Messi’s success helped to drive him. “I’m sure the competition between us motivates him too. It’s good for me, good for him and good for other players who want to grow,” he said. It is, he could have added, good for us all.

For four years Ronaldo had finished second to Messi but he had not given up. Instead, he took the trophy off Messi two years in a row. A year before, his tears had shown what it meant to him. Now he said: “This is my third Ballon d’Or but I am not going to stop here. I want to catch Messi.” Two months later, it is tempting to look back on that moment and imagine Messi silently sitting there and thinking: “Oh, will you now?” Maybe Ronaldo was right; maybe he does motivate Messi, too.

The Ballon d’Or ceremony in Zurich was on 12 January. Real Madrid had just won the Club World Cup. They were top of the league table and Ronaldo was the pichichi, La Liga’s top scorer. Messi was second, but he was 10 goals behind: 16 to 26. They had met just once, in October, and Madrid had won 3-1, the first time they had defeated Barcelona by more than one goal in six years. Olés had rung around the stadium. Ronaldo had scored, Messi had not.

On Sunday night they meet again and everything has changed for the players and the clubs they embody, the greatest rivalry in football condensed into the two teams’ most emblematic players, men who have engaged upon an individual battle that may never have been seen before. Messi is now two goals in front, 32-30, and Barcelona are top of the table. Win at the Camp Nou and they will go four points clear, a big step towards a title that appeared impossible not so long ago.

Xavi Hernández once described Real Madrid and Barcelona as being like two sides of a scales: there’s something in the symbiotic relationship between them that means they cannot both be up at the same time, even if both are playing well. That has not always been true of the two players who define them, but it is this time. “Going up, going down,” ran the gleeful headline on the cover of the Catalan sports daily El Mundo Deportivo this week, alongside pictures of the pair.

Cristiano Ronaldo and Lionel Messi at the Ballon d’Or ceremony in January. Photograph: Action Press/REX

“2015 has already begun and there are more titles to be won,” Ronaldo had said that night in Zurich. The year started badly for Messi. He was left out as Barcelona were beaten at Real Sociedad, precipitating a crisis in which the sporting director departed and the president called elections. Luis Enrique, the coach, denied he had been handed an ultimatum but something was not right. Reports emerged of a breakdown in his relationship with Messi; the central defender Jérémy Mathieu later confirmed there had been a confrontation in training.

But two months on, things look different. Messi looks different. The presidential adviser Charly Rexach said in one interview that Messi had eaten “too many pizzas” last season and this week El Mundo Deportivo reported that with the aid of a new nutritionist he has shed 3.5 kg (8lb). The pictures “proved” it, although there was something telling in the fact that all three pictures – from 2013, 2014 and 2015 – showed him, shirt off, ball in hand having just scored a hat-trick. One team-mate told a friend in August that Barcelona would have a good season. Why? “Because Leo is up for it.”

Messi was not exactly playing poorly before but there has been an improvement in him and others. The first league game after that defeat to Sociedad was against Atlético Madrid at the Camp Nou and Messi was hyperactive in an impressive win. Afterwards, he came out and dismissed the reports as “lies”. That was the start of a run in which Barcelona have won 18 of their last 19 games, reaching the Copa del Rey final and Champions League quarter-finals. “We’re more intense,” Messi admitted.

The performance against Manchester City drew the kind of child-like reaction from Pep Guardiola that was more eloquent than adjectives could be. Javier Mascherano said: “Football controls us all but Messi controls football. He is a legend, doing things mere mortals cannot aspire to.” Messi noted: “It turns out that I have gone from being a disaster to being in my best moment.” He has now scored 32 goals and provided 14 assists in the league, plus a further 55 “assists” not taken by team-mates. In total, he has 43 goals and 21 assists, accounting for more than half of Barcelona’s goals. He has scored 20 goals in 2015 alone.

Ronaldo, meanwhile, has nine. He was sent off against Córdoba for kicking and slapping Cordoba’s Edimar. There have been doubts about his fitness and his happiness. After Madrid were beaten 4-3 by Schalke , in which he scored two and watched in anger as the team collapsed around him, he announced he would not talk for the rest of the season.

He did not score in his last game against Levante, the night after Messi had gone ahead of him for the first time this season. His frustration was clear and externalised too, when a shot of his was cleared off the line and Gareth Bale turned the ball in. Supporters even whistled him at one point, to which he nodded his head as if to say: “Oh, I see,” and then muttered “foda-se”, effectively “unbelievable” – which, when you consider what he has achieved for Real Madrid, it is.

This, after all, is the man who will leave Real Madrid as the club’s all-time top scorer, the man who took the Ballon d’Or from Messi and announced he wants to do it again.