A few scornful eyebrows will have been raised this week when Marcos Rojo announced that Ángel Di María is the most talented player in the Manchester United squad. Allowing for Rojo’s understandable bias towards his fellow Argentinian, I’m inclined to agree with him – even though there is a possibility that the winger might not be alongside Rojo in a United shirt when next season starts.

Many of Di María’s long-term admirers regretted his failure to confirm the good impression made by a bright start to his Old Trafford career. His resurgence in the Copa América, when his two goals against Paraguay on Tuesday helped Argentina to Saturday’s final against Chile in Santiago, will have felt like a vindication.

This was a glittering return to form. Everything Di María did at his best, he was doing again. Once more he was looking like a player capable of seizing a big occasion and making the difference.

Di María is unveiled by United manager Louis van Gaal Photograph: Steve Parkin/AFP/Getty Images

In Beijing, seven years ago this week, I watched him score the only goal of the Olympic football final between Argentina and Nigeria, at the age of 20. Thirteen minutes into the second half he sprinted on to a pass stroked behind the full-back by Lionel Messi and, in front of a crowd of 89,102 in the Bird’s Nest, chipped the ball calmly over Ambruse Vanzekin, the west African side’s goalkeeper, presenting victory to Diego Maradona’s team.

Di María was a Benfica player then, having moved to Portugal a year earlier from Rosario Central, his hometown club, for a fee of €6m. Two years after the Olympic triumph he was on his way to Real Madrid. This time €25m changed hands, but over the next four seasons at the Bernabéu no one was ever given reason to think that the sum represented poor value. Even when he got himself sent off in the 31st minute of extra time in the final of the Copa del Rey against Barcelona in his first year, he had already provided the cross from which Cristiano Ronaldo scored the winner.

Di María was named man of the match in the 2013-14 Champions League final. Photograph: Jasper Juinen/Getty Images

After a difficult start to his second season, he had fully re-established himself by the time the team won La Liga. In his fourth season in Madrid, after Carlo Ancelotti had replaced José Mourinho, he topped the league’s table of assists and was named man of the match in the Champions League final, when Real beat Atlético Madrid 4-1. It was his dribble and shot in the 20th minute of extra time that provoked the rebound headed home by Gareth Bale to give Real a 2-1 lead.

These extra-time interventions are no coincidence. Among Di María’s virtues is a refusal to give up. He may not be the most elegant of players, or the most efficient in terms of statistics, and his relatively unphotogenic angularity may even have been one of the reasons why Florentino Pérez decided to replace him with the baby-faced James Rodríguez last summer – the president’s most misguided decision since the offloading of Claude Makelele in 2003. But Di María knows that, as long as the game is in the balance, it’s never too late to strike a decisive blow, and his athleticism gives him the capacity to act on that belief.

The quintessential Di María moment arrived in São Paulo during the 2014 World Cup finals, when Argentina struggled to beat Switzerland in the round of 16. In a notably poor match, a statistic showed that he had lost possession no fewer than 51 times for Alejandro Sabella’s side when, in the last 10 minutes of extra time and with Argentina starting to despair, he suddenly hit a couple of fierce long-range shots, the first tipped over and the second deflected away from goal. And then, in the 117th minute, he swooped in from the right to accept Messi’s pass and strike the sweetest of first-time shots with his left foot inside the far post.

Di María endured a difficult first season at Manchester United Photograph: Matt West/BPI/Rex

How many head coaches would have allowed a player who had conceded possession more than 50 times to stay on the pitch for the whole two hours of such a vital contest? It is not a statistic that would impress most managers in the Premier League. But Sabella trusted him and received the reward. Sadly, a torn thigh muscle in the quarter-final against Belgium – after helping to create Gonzalo Higuaín’s decisive goal – cost Di María his place first in the semi-final and then in the final against Germany, a match settled by a single late goal, in which his presence could well have been decisive.

Several reasons have been advanced for his poor season in England following his £59.7m transfer to United, which began with the club’s player of the month award for September but was interrupted by a hamstring injury in November and ended with only one start in the last eight league fixtures. There was the distress caused by the need to move his wife and 22‑month‑old daughter into a Manchester hotel in February after thugs wielding metal poles tried to break into his home while the family were having dinner, only hours after he had performed well in a home win over Leicester City. A month later he grabbed the referee’s shirt after being booked in an FA Cup sixth-round match against Arsenal and was sent off. It seemed increasingly likely, too, that he did not really fit into the patterns of play adopted by Louis van Gaal.

But in Concepción on Tuesday he drew the foul that allowed Lionel Messi to guide in the free-kick from which Rojo gave Argentina the lead against Paraguay. In the second half he moved on to Javier Pastore’s pass to make it 3-1 with a close-range shot angled across the goalkeeper. Argentina’s fourth goal came when he clipped home the loose ball after Pastore’s shot had been blocked. His precise cross laid on the fifth, scored by the head of Sergio Agüero.

Di María celebrates after scoring against Paraguay Photograph: Yuri Cortez/AFP/Getty Images

He had nothing to do with the second or the sixth goals, and Messi gave the match its outstanding individual performance. But Argentina’s No 7 had used the 90 minutes to rebuild a reputation badly damaged, at least in English eyes, by his difficult first season in the Premier League.

When he feels trusted, as he was by Maradona, Mourinho, Ancelotti and Sabella, Di María is the sort of player who can undermine the obsession with number-crunching that threatens to asphyxiate sport. Wherever he plays next season, whether at Old Trafford or the Parc des Princes, it would be good to see him striking further blows for individual expression in an increasingly conformist football world.