I would say that they are strong enough to beat Bayern but at the same time the situation is too close. Normally I would give the win to Bayern, because Barcelona has been bad and they are still not recovered yet because they may have a good roster but they need to show and proof they are ready again for a long time.
In fact, Barcelona isn't strong enough to beat Bayern. They are defeated with 2 goals, without scoring any goal (Bayern 2 - 0 Barcelona).
Barcelona may be stronger right now, but they still don't have the mentality to beat a big team like Bayern Munich. Especially, since Lewandowski is a Bayern former player, Bayern players know well how to stop Lewandowski from scoring. Look at the result today, Lewandowski can't score a single goal. Another factor is that Xavi looks not choose the right players for the midfield line. I'm surprised Xavi didn't put Frenkie de jong and Kessie as the starters. Barcelona has many rosters, but they don't know which ones are best to be the starters.