Frenkie de Jong underlines his credentials as Barcelona's new midfield general

Lionel Messi and Frenkie de Jong were on target as Barcelona came from behind to beat Rayo Vallecano 2-1 (stream the replay on ESPN+ in the U.S.).and book their place in the last eight of the Copa del Rey.

Second-tier Rayo took the lead against the run of play when Fran Garcia tapped home in the 63rd minute after good play from substitute Alvaro Garcia.

- Copa del Rey: Stream LIVE matches on ESPN+ (U.S. only)
- Barca release special Clasico kit to be worn vs. Real Madrid

Barca, who had been denied by the woodwork three times prior to Rayo's opener, responded quickly, with De Jong and Antoine Griezmann combining to set up Messi for his 15th goal of the season in the 69th minute.

The comeback was complete in the 80th minute, when Messi freed Jordi Alba to square for De Jong to continue his recent flurry of goals.

Positives

With Real Madrid and Atletico Madrid out, the Copa is Barca's best bet of a trophy this season. While it would be third on their list of objectives, after La Liga and the Champions League, any silverware will be welcome after a trophy-less campaign last time out.

Once again, De Jong was immense. The Netherlands international has transformed his game in recent weeks, getting forward much more, and the numbers demonstrate it. He's scored four goals and set up two more in the last seven games. He's not going to rest on his laurels, mind.

"I can still play better," he told DAZN after the full-time whistle.

Negatives

Clement Lenglet looked slow for the Rayo goal and has now been responsible for too many goals that Barca have conceded this season. Wasteful finishing could have cost Barca again, too, although they reacted well to going behind in the end.

Manager rating out of 10

6 -- Ronald Koeman got the balance right with his starting XI, picking a strong side but also handing chances to Junior Firpo, Riqui Puig and Francisco Trincao. He also reacted quickly to going behind, throwing on Alba, Pedri and Ousmane Dembele immediately.

Player ratings (1-10; 10 = best. Players introduced after 70 minutes get no rating)

GK Neto, 6 -- Maybe could have done better with Alvaro's cross-shot which led to the goal, but certainly wasn't to blame. Reliable other than that.

DF Oscar Mingueza, 6 -- The youngster is solid enough in defence but wastes the ball too often in the final third.

DF Ronald Araujo, 7 -- Barca's best defender on the night. Dominant in the air and covered Lenglet well when he had to.

DF Clement Lenglet, 5 -- Had a nightmare for the Rayo goal, beaten far too easily for acceleration by Alvaro. His form's a concern.

DF Junior Firpo, 5 -- Got in some good positions on the left and was regularly found by Messi but touch and final pass let him down.

MF Sergio Busquets, 6 -- Suspended for Sunday's game against Athletic so started against Rayo. Read the game well. In good form.

MF Frenkie de Jong, 8 -- Fast becoming one of Barca's best players. Drives forward with pace and power, can pick a pass (like the one for Griezmann leading to Messi's goal) and has now added goals to his game.

MF Riqui Puig, 6 -- Looks comfortable in the side, asking for the ball and trying to keep it moving quickly. Hit the post in the first half. Should get more chances in the coming weeks now Barca are playing 4-3-3 more regularly.