Barcelona continued their perfect start in the Champions League and warmed up for the Clasico at the weekend with a 2-1 win over Shakhtar Donetsk on Wednesday.

The Spanish champions held off their Ukrainian visitors to take their third win from three games and put one foot into the knock-out stages after failing to progress in the past two seasons.

Ferran Torres opened the scoring for Barca with 20-year-old midfielder Fermin Lopez smashing home the second from the edge of the box.

After 17-year-old debutant Marc Guiu struck the winner against Athletic Bilbao at the weekend, Lopez's display meant it was another fine night for Barcelona's La Masia talent factory.

Heorhiy Sudakov pulled one back for Shakhtar after a Barca defensive lapse, creating a nervy finale for the hosts, but they held on to the three points.

Barca took forward Joao Felix off hurt in the final stages, with another injury to add to a long list the last thing they need.

Barcelona were already without several key players, including Robert Lewandowski, Pedri and Frenkie de Jong, leading Xavi to deploy winger Torres in the middle of the attack.

The former Manchester City player said he was ready to step up a level in an important week for the club, with Real Madrid visiting on Saturday.

He started brightly and hammered home before the half-hour mark after Ilkay Gundogan sweetly teed up Lopez, whose effort came back off the upright.

The goal was initially ruled out but VAR showed Lopez had timed his run to perfection to reach the German midfielder's nicely weighted chip over the top.

Lopez, who made his debut in August, rescued Barcelona a draw earlier this season at Real Mallorca and staked his claim for a start against Madrid with his best performance to date, in for the suspended Gavi.

Dmytro Riznyk had saved well from the midfielder early on but could do nothing about his goal, a cannonball strike, in off the post to shore up Barca's position.

Riznyk did well to save a Felix header early in the second half and was relieved to see the offside flag up against Torres as he clipped home after an hour.

Just a couple of minutes later, Shakhtar earned a foothold in the game.

Joao Cancelo did not get back into position after yet another foray forward, and Oriol Romeu was left in the dust by Sudakov, who finished well at the near post.

It was the first goal Barcelona have conceded in the campaign.

Lopez hit the post with another long-range effort and then had a header ruled out for offside as he continued his all-action display.

Barcelona wound down seven minutes of stoppage time to take the points as supporters in the stands turned their attention to the impending Clasico.

Shakhtar are third, provisionally level with second-placed Porto on three points, who visit bottom side Antwerp later, while Barcelona lead with nine.