This was almost the exact opposite of third seed Alcaraz's dominant first-round win against lucky loser JJ Wolf.

The 21-year-old still had a compression sleeve on his right forearm - an injury which impacted his preparations for Roland Garros - and his lack of match practice showed.

After a relatively straightforward first two sets, it was as though Alcaraz's concentration began to drift, often following a good shot with one that sailed wide or found the net.

He made 47 unforced errors, most of which came in the third set as he quickly went a double break down.

It looked as though the match could get even trickier for Alcaraz as he was immediately broken at the start of the fourth set, once again on a long forehand.

However, he seemed to re-engage in the next game as he got to 30-30 on the De Jong serve. His team did their best to encourage him and, as De Jong sent a forehand into the net, Alcaraz seemed more like himself.

The two traded breaks once again, with the set level at 2-2 before Alcaraz pulled away, helped by a tiring De Jong, who beat Britain's Jack Draper in five sets in the first round.

Alcaraz will, howeve, know that tougher tests await as he attempts to secure a third major title.

"The energy that I received from the people to forget about the third set and be at my best in the fourth set was really helpful to me," he added.