Midfielder 'Leo' played twice against Ukraine in Norway's doomed qualification attempt.
Poland eventually ran away with the group that also included Simon Davies' Wales and Ukraine booked their play-off place by virtue of finishing second.
The Spurs team-mates face each other in Kiev today and Dortmund on Wednesday for the right to travel to Japan and Korea next summer.
Leo explained: "Ukraine have a very good team, a lot of good players and it's not going to be easy for Germany.
"Even if Germany do well in Kiev, Ukraine can still do well away from home because of the way they play. They sit back and are very quick on the counter-attack and are always dangerous with Sergei and Andrei Shevchenko up front.
"Ukraine were more in charge when we played them in Ukraine but we were prepared for that, played well defensively and drew 0-0.
"At home we lost 1-0. We had a lot of chances but they are always dangerous and in the end they scored with Shevchenko. If they get a good result at home then I think they will have a big chance."
However, Leo insisted Germany were favourites and was sure they would come back from the disappointments of firstly being hammered by England and then having their place in the World Cup snatched away by David Beckham's last-minute free-kick in the final round of qualifying games.
"You always know that the Germans will come back," he said. "They are always in the final and it will be strange without them.
"They have gone through hard times and they have older, experienced team and it doesn't like youngsters are coming through.
"It will take time for them to get a really strong team again but they have good players, experience and they are very strong mentally. In a game like this they will show that mental strength."
So what about a prediction? "It is easy to say Germany but I know all about how dangerous Ukraine can be," added Leo.
"It's a massive game for both teams. Germany have the more experience but you have to watch out for Ukraine. For me, it is very open."
Christian Ziege and Sergei Rebrov go into battle for a place in the World Cup today and although he can barely pick between them, Oyvind Leonhardsen is well aware of the threat Ukraine might cause Germany.