FRANKFURT, Germany (AP) Robert Lewandowski was so sure he would score again that he was already wearing the t-shirt marking his achievement. When the Bayern Munich striker struck in Mainz, he lifted his jersey to show off a t-shirt with the number 100 spread across, celebrating his 100th Bundesliga goal.

''You always have to believe you will score,'' Lewandowski later said.

He could have worn one with 101 as well, since he notched Bayern's second goal too in the 3-0 victory. Bayern is off to a tremendous start as it hosts Dinamo Zagreb in the Champions League on Tuesday.

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In the other Group F match, Arsenal hosts Olympiakos with both teams seeking to get their campaigns back on track after opening-round losses.

Here are some things to know about Tuesday's matches:

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LEWANDOWSKI'S RECORD

Lewandowski has seven goals in his last two games - including five in less than 10 minutes against Wolfsburg - and tops the Bundesliga with 10 goals in seven matches.

The last player to score 10 goals in the first seven matches was the legendary Gerd Mueller, 44 years ago. Mueller finished the season with 40 goals, still a record.

''No, no, no,'' Lewandowski said when asked if he believed he could reach or top that mark.

The immediate award was Bayern coach Pep Guardiola's permission for a visit to the Oktoberfest.

Bayern, which opened its European campaign with a 3-0 win at Olympiakos, has all the reason to celebrate - it tops the Bundesliga with seven wins in seven games, with a 23-3 goal difference.

Lewandowski became the fastest non-German player to score 100 in the Bundesliga, reaching that mark in his 168th appearance. Bayern's seven wins and the +20 goal differences at the start of the season is also a league record.

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DINAMO'S STREAK

Dinamo arrives in Munich with an impressive run itself - the Zagreb side is unbeaten in 45 straight matches across all competitions.

By beating Arsenal at home 2-1 in the opening round, Dinamo ended a 16-year winless run in the Champions League.

Asked if he was worried about Lewandowski's form, Dinamo coach Zoran Mamic joked that the striker was ''rapidly losing form. He scored five and now only two.''

Mamic said it was a ''privilege to play against probably the best team in the world.''

''It's a reward for all the work we've invested recently. We will try to produce a wonder, like we did against Arsenal,'' he said.

But Mamic insisted Dinamo would not ''park a bus'' in front of its goal, adding ''that's not the idea.''

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DEJA VU

Arsenal and Olympiakos have met three times in the past six seasons. Each of the six preceding games has been won by the home team.

Striker Olivier Giroud was sent off in Zagreb and is suspended for the match against Olympiakos.

Arsenal is unbeaten at home in eight matches against Greek teams, but it also has a 5-5 win-loss record in the last 11 matches at home in the competition.

Olympiakos has won its first five games of the Greek season.