The European champions face Tigres in the final on Thursday after the Mexican club saw off Brazilian giants Palmeiras in Sunday’s other semi-final.
“It was a very good match and we’re ready for the final,” Lewandowski said.
He gave Bayern the lead with just 17 minutes gone at the Ahmad Bin Ali Stadium, a host venue for the 2022 World Cup in Qatar.
The Poland star then headed home a pinpoint Leroy Sane cross four minutes before the whistle to book Bayern’s place in the final.
Lewandowski, the Bundesliga’s top scorer, has now scored 29 goals in 27 club matches this season.
And the MOTM is…. 🥁 #LewanGOALski @lewy_official #TheBest #FinalMissi6n https://t.co/A8KjVKuz1h
— FC Bayern English (@FCBayernEN) 1612815600000
Bayern are bidding to become only the second team after Barcelona in 2009 to win all six domestic and international titles up for grabs in one season.
The German giants lifted the Bundesliga, German Cup, Champions League, German Cup and UEFA Super Cup trophies in 2020.
“We want to claim another title — title number six during this season,” Lewandowski added.
“This is a World Cup, which is always something special. I hope we can play even better in the final and that we will have more goalscoring chances.”
The European champions ended Ahly’s 32-match unbeaten run in all competitions under their South African-born coach Pitso Mosimane.
The African Champions League winners struggled to get near the Bayern goal as the Germans enjoyed 70 percent possession.
Strong game from the boys today…finals here we come 💪🏾 #AD19⚡️ https://t.co/qrTPvWZhzF
— Alphonso Davies (@AlphonsoDavies) 1612820485000
Despite the efforts of two defenders lunging to block his shot, Lewandowski put Bayern ahead with a crisp finish from a Serge Gnabry pass.
The Poland striker could have made it 2-0 towards the end of the first half when Joshua Kimmich drew the defence, but Lewandowski fired over the bar.
Ahly grew in confidence at the start of the second half and created half-chances as the Bundesliga leaders showed signs of fatigue.
Heavy snow in Berlin on Saturday meant Bayern had a seven-hour delay to their flight to Doha and the Germans’ tempo dropped after Lewandowski’s early goal.
With an eye on Thursday’s final in Al Rayyan, Bayern coach Hansi Flick replaced forwards Thomas Mueller and Gnabry for the final half-hour.
It was the fresh legs of Gnabry’s replacement Sane which created space to serve up a late cross that Lewandowski headed home to wrap up the win.