Robin van Persie is showing true class for the Gunners [GALLO/GETTY]

Emmanuel Adebayor also scored twice as the Gunners overcame a strong start by the 2004 European champions to dominate for most of the match.

Champions League newcomers Bate Borisov held Juventus to a 2-2 draw in Belarus to go third in Group H.

Real Madrid are top of the group after a 2-1 win away to UEFA Cup champions Zenit St Petersburg on Tuesday.

Fenerbahce and Dynamo Kiev played out a goalless draw in Group G.

Demolition job

Arsenal demolished a feeble Porto side at the Emirates to go a point ahead of their opponents at the top of Group G.

Dutchman Van Persie settled some early Arsenal jitters to slot the opener after 31 minutes before Adebayor headed the second shortly before half time.

Porto, who have never won in England, capitulated after the break and Van Persie waltzed through to make it 3-0 before Adebayor converted a penalty with 19 minutes remaining.

Arsenal manager Arsene Wenger had been critical of his side's attitude after a shock 2-1 home defeat against Hull City on Saturday that cost them top spot in the English  Premier League.

Devastating

"I didn't want to punish the players after the Hull defeat. Sometimes you give a team the chance to respond," Wenger said.

"It was what I expected, we could have scored more but we responded in a convincing way. I expect us to win the group from here."

The first goal came as Adebayor surged to the byline and calmly pulled the ball back for Van Persie, who shot past Helton at the near post.

Porto's slim hopes of a revival evaporated five minutes before the interval when Adebayor climbed high to head Arsenal's second goal from a corner.

Van Persie brushed off a weak tackle to poke a shot past Helton just after the break.

Adebayor completed the rout from the penalty spot after Nicklas Bendtner was needlessly fouled by Freddy Guarin.

Spirited

Fatih Tekke shows the frustration as Zenit lose to Real [AFP]

An own goal by Zenit defender Tomas Hubocan and an opportunistic strike by Ruud van Nistlerooy gave nine-times European champions Real their second straight victory in Group H.

Portugal international Danny, Zenit's record $40 million signing last month, was on target for the Russian champions midway through the first half but the home side wasted numerous chances after the break.

The UEFA Cup holders, making their Champions League debut this season, are still looking for their first points in the competition after going down 1-0 at Juventus in their opener two weeks ago.

Real broke through when Hubocan inadvertently redirected a Rafael van der Vaart low cross from the right into his own goal.

Andrei Arshavin led the fightback, setting up the equaliser by crossing for Danny, getting in front of his marker, to volley home in the 25th minute.

Then another defensive breakdown by Zenit allowed van Nistlerooy to beat Malafeyev with a low shot into the far corner on 31 minutes.

"We have only ourselves to blame," Arshavin told Russian television.

"We had so many chances but couldn't put them away while Real made them count.

"I don't want to put everything down to luck, probably their bigger class made the difference tonight."

Juve salvage pride

Igor Stasevich (L) was on the scoresheet for an impressive Bate Borisov [AFP]

Italy forward Iaquinta saved the Serie A side's blushes by nodding in a Sebastian Giovinco cross in the 29th minute and firing through the legs of Bate keeper Sergei Veremko on the stroke of half time.

The hosts had taken control with goals by Sergei Kryvets and Igor Stasevich on 17 and 23 minutes.

After two matches Juventus, who beat Zenit St Petersburg 1-0 in their opener, are second in Group H with four points, two behind leaders Real Madrid.

"They surprised us. We couldn't hold them in any area of the field. It was a nightmare first half hour," Juve coach Claudio Ranieri told Sky television.

"We did well not to give up. We have to compliment these lads from Belarus. They ran like there were 22 of them, not 11."

BATE made a fearsome start and Kryvets gave them a deserved lead when he ran on to a long pass, rounded Alexander Manninger and slipped the ball into an empty net.

Stasevich headed past an immobile Manninger, standing in for Italy keeper Gianluigi Buffon, after Pavel Nedved failed to cut out a Pavel Nekhaychik cross to double the lead.

Lacklustre

Fenerbahce and Dynamo Kiev played out a lacklustre 0-0 draw, leaving both teams with much to do to get their Group G campaigns going.

Fenerbahce playmaker Alex worked to create chances up front with Daniel Guiza but the home side gave the ball away easily and Dynamo comfortably absorbed the pressure.

The result piled fresh pressure on Fenerbahce's Spanish coach Luis Aragones, who won Euro 2008 in the summer.

Last season's Champions League quarter-finalists are 10th in the domestic league.