The Ukrainian champions held Bayern to a 0-0 draw in Lviv last month but Guardiola's side will be expected to ensure progression to the last eight at the Allianz Arena this week.
While Guardiola is confident, the Bayern boss warned of the quality Shakhtar will pose through the likes of Douglas Costa and Luiz Adriano.
"I'm optimistic. I have complete faith in my team," explained Guardiola, who will be without Philipp Lahm despite the full-back's recent return to training following an ankle problem.
"They have the same quality as the big teams in Germany. Their gameplay is super aggressive, as in Germany, and they are quick on the counter-attack, again like here.
"If they played in the Bundesliga, they would contend for the title and if we let Shakhtar's attackers run, we will have big problems because they have plenty of quality.
"Many may not know the players of Donetsk well, but they have great quality. We want to control the game tomorrow like in the first half of the first leg."
Franck Ribery was also present at Tuesday's pre-match news conference, with the Frenchman in confident mood ahead of the second leg.
Asked about Guardiola's advice, Ribery explained: "He always makes us better, we are ready and that's important.
"Of course it was a funny game there in the first half, we did very well in the second half but it is now a completely different game - we play at home, we are all fit and that's important.
"We are perhaps better than Shakhtar, but in the Champions League it is not easy.
"We know the situation from the first leg and we have to win, Shakhtar is a very good team but we are very focused."
