The Champions League holders defeated their English opponents Arsenal F.C. 3-1 in the same stage of the competition at the Emirates last year.
"It's a good test for us. Tomorrow we will know what our level is in Europe this year," Spaniard Guardiola told a news conference on Tuesday.
"You can't dominate for 90 minutes against Arsenal, it's impossible. You can play good and maybe dominate one half or 75 minutes but never the full game. With their quality of players you can always have problems.
"We won't think about the second game, we're just concentrated on what we have to do tomorrow."
Bayern have lost only once in 34 games and have won 13 successive Bundesliga matches but Guardiola wants to guard against the complacency that caused the eventual champions to lose 2-0 at home in the second leg against Arsenal 12 months ago.
"We have to accept that every game we are favourites and that we are favourites to retain the title, I can't deny that," he said.
"I'd like to live without these feelings but I can't. But tomorrow we start 0-0," Guardiola added.
"Always with the ball they (Arsenal) are organised and in good shape. Once we let them (have) the ball we will suffer. We must dominate the ball."
Guardiola, who won the Champions League as Barcelona coach in 2009 and 2011, took over from Jupp Heynckes last year after the German coach guided Bayern Munich to three trophies last season.
But the master tactician played down his team's chances of being the first club to retain the European title in the Champions League era.
"My target is to play every week better than the last. To retain the title is so difficult, so I'm not worried about that," the former Barcelona midfielder said.
"I know as a sportsman how difficult it is to win everything one year and then win again. We are just going to fight against one of the best teams in Europe (Arsenal F.C.) and then will we see the level."
Bayern thrashed Freiburg 4-0 in the Bundesliga on Saturday to extend their unbeaten league run to 46 games. Their only loss in this season's Champions League group stage came at home to Manchester City, with qualification already assured.
France winger Franck Ribery will miss the match in London with a buttock injury and fellow midfielder Xherdan Shaqiri, who scored twice against Freiburg, will miss out with a thigh strain.
Arjen Robben, who scored the winning goal in Bayern's 2-1 win over Borussia Dortmund in the Champions League final last season, is fit.
"Especially after last season where we won everything I think it has been good that a fresh wind came in," the 30-year-old Dutch winger said.
"As players we had to be focussed from the first day onwards and go with this new coach, and his new plan.
"We had a great result last year but it's going be a very different game. We're going to try to play our own game and try to win again."