Nowitzki made four free throws in the last 19 seconds and Germany stayed alive in the European Championship by edging Turkey 73-67 on Friday.
"Sometimes it's not always the most beautiful basketball. We only scored six points in the first quarter but the good thing was that the defence was good. We had only given up 13," Nowitzki said.
Nowitzki scored 19 points for Germany, 13 of them in the second half.
Germany trailed 26-23 at halftime but came with some big points down the stretch to claim the win it needed so desperately.
"We talked at halftime about how it was one of the worst halves that we have ever played. But we were still only down three points," Nowitzki said.
"We saw everything positively, and in the second half we really played as a team and hit some important shots. It was good enough."
Chris Kaman, the Los Angeles Clippers centre, led Germany with 20 points. He and Nowitzki had seven rebounds each.
Chicago Bulls backup centre Omer Asik, coming back from a broken left fibula, led Turkey with 19 points and 11 rebounds.
Nowitzki, the MVP of the NBA final after taking the Dallas Mavericks past the Miami Heat for the title, is trying to take Germany to its second straight Olympics.
The two finalists from this tournament will qualify for next year's Games in London, while the next four teams will go to an additional qualifying tournament.
Germany's progress to the quarter-finals here will depend on other results.
"We overcame the first hurdle and now we have to see what the other teams do. I hope that we can have a bit of a final on Sunday and that the place is packed," Nowitzki said.
Spain, the defending champion, has no such worries after making the last eight with a dominant performance from the Gasol brothers in a 84-59 tour over Serbia.
They combined for 46 points and 18 rebounds.
The brothers dominated in the paint, scoring 42 of their points from close range. In one stretch in the second quarter, Pau Gasol scored seven points and Marc Gasol added four in an 11-0 run.
Spain led by as many as 29 at one point.
"To hold a team that's been scoring 80 to under 60 is a great achievement," Spain coach Sergio Scariolo said. "We came in with great concentration and immediately established our high-tempo game. We are still not shooting that great, that's the only problem."
Serbia, which was led by Nenad Krstic's 12 points, has lost three straight matches but can still advance if it beats Turkey in its final Group E game. Turkey is the only team to have beaten Spain at this year's tournament.
Spain beat Serbia in the European final two years ago, but then lost to the Serbs in the world championship quarter-finals last year.
This time, it wasn't a contest.
"They hurt us very badly and we didn't defend as usual," Serbia guard Stefan Markovic said. "Now we have to focus on the last game."
Spain used all 12 players, and all scored. Serbia, however, played without guard Aleksandar Rasic, who missed the game with a back problem.
Milos Teodosic, the Serbia guard whose three-pointer at the buzzer beat Spain at the world championships last year, was held to six points.
"We wanted to stop Teodosic and we did it," said Spain guard Jose Calderon, who plays for the Toronto Raptors.