PIX: Barca young guns rout BATE, Chelsea through to last 16

Already-qualified Barcelona showed they have plenty of exciting talent bursting through the ranks when a team of youngsters lit up the Nou Camp in a 4-0 drubbing of basement side BATE Borisov in Champions League Group H on Tuesday.

The holders had comfortably reached the last 16 as group winners last month and coach Pep Guardiola blooded a slew of recent youth-team graduates in a starting lineup in which the 10 outfield players had an average age of 21.4.

Teenage midfielder Sergi Roberto opened the scoring against the Belarussian champions in the 35th minute when he stroked a loose ball low past goalkeeper Aleksandar Gutor.

Fullback Martin Montoya powered a shot high into the net for a 60th-minute second before Pedro scored the third three minutes later with an audacious flick and then converted a penalty two minutes from time after a foul on winger Isaac Cuenca.

Barca's tally of 20 goals in their six group games equalled the record set by Manchester United in the 1998-99 season as the Catalan club seek a fifth triumph in Europe's elite club competition and a third in four years.

Guardiola had the luxury of being able to rest most of his first-choice players with Saturday's opening La Liga 'Clasico' of the season at great rivals Real Madrid looming.

World Player of the Year Lionel Messi, playmakers Xavi, Andres Iniesta and Cesc Fabregas and keeper Victor Valdes were all left out of the squad and Spain forward Pedro was the only player in the starting 11 who could be considered a regular.

Tuesday's side, dubbed 'Baby Barca' in local media, included brothers Thiago Alcantara, 20, and 18-year-old Rafinha, whose Brazilian father Mazinho played professionally in Italy and Spain.

The promising Cuenca has shone on several previous appearances for the first team and it was his delicate pass that sent Montoya clear for Barca's second and his low cross that created their third and the first of Pedro's two goals.

BATE coach Viktor Goncharenko said some of the Barca players on display on Tuesday were possibly the Messis and Xavis of the future.

"Obviously the level of Messi and Xavi is extremely high but these players can get close to that level too," he told a news conference.

Unbeaten Barca finished with 16 points from their six matches, seven ahead of Serie A champions AC Milan, who were already assured of second place and drew 2-2 at third-placed Viktoria Plzen with the Czech side dropping into the Europa League.

BATE could have grabbed third but that would have needed a win at the Nou Camp for starters. The Belarussians had no chance against Barca's exciting second string.

Chelsea spared themselves an anxious night with a comfortable 3-0 win over Valencia to book a berth in the last 16 on Tuesday.

Chelsea began their final Group E match at home to Valencia with their hopes balanced on a knife edge, knowing they need a win to be sure of qualifying.

Once Didier Drogba fired them ahead after three minutes, however, the nerves disappeared and Ramires's strike in the 22nd knocked the stuffing out of Valencia who were also vying for second spot.

Drogba, back to his best, struck again in the 76th minute with a neat finish to snuff out Valencia's rapidly fading hopes of snatching a place in the knockout round.

Chelsea manager Andre Villas-Boas said his team's performance was indicative of their recent defensive improvements and the victory was a very good emotional win before next week's Premier League clash with Manchester City.

"Our defense is not that bad and we have been improving a lot," the Portuguese, who has been under the spotlight after a run of poor results, said.

Olympique Marseille snatched a last-gasp 3-2 victory at Borussia Dortmund to reach the Champions League knockout stages.

Zenit St Petersburg also grabbed a place among Europe's elite thanks to a gritty 0-0 draw in Porto.

All seemed lost for Marseille when they trailed the German champions 2-0 after 32 minutes and rivals Olympiakos were beating Group F winners Arsenal in Greece but Loic Remy gave them a lifeline when he scored in first-half stoppage time.

Dortmund, who began the night with a remote chance of qualification, finished bottom.

"This win will be engraved in the history of Marseille," coach Didier Deschamps said.

"Football is marvellous when you win. We believed right until the end, both the players and the fans."

Olympiakos had looked like taking second place as they marched toward a 3-1 victory over Arsenal but Marseille's Houdini act means the Greek side have to settle for a place in the last 32 of the Europa League instead.

Already-qualified AC Milan finished distant runners-up behind the Spanish champions, signing off for the winter break with a 2-2 draw at third-placed Viktoria Plzen despite leading 2-0 until the 89th minute.

Bayer Leverkusen's 1-1 draw at Racing Genk provided an added bonus for Chelsea who go into next week's draw for the last 16 as group winners instead of the Germans, meaning they will avoid the likes of Barcelona, Real Madrid and Bayern Munich.

Genk were on the verge of a first Champions League victory courtesy of a Jelle Vossen volley but Eren Derdiyok equalised late on to safeguard the Bundesliga side's record of never having lost to a club from Belgium.

Zenit's draw in Porto kept them in second place a point above the Portuguese and behind surprise Group G winners APOEL Nicosia whose 2-0 home defeat by Shakhtar Donetsk was academic as they had already become the first Cypriot side to reach the knockout rounds of the competition.