With Alexander Zverev and Dominic Thiem already out of the competition, Federer's path towards a second consecutive Halle title is clearing - and that continued on Thursday.
The opening set needed to be decided via a tie-breaker which Federer dominated 7-1.
Federer skipped the entire clay-court season for the second year in a row and is now just four wins away from matching Jimmy Connors' all-time record of 174 victories on grass.
Kudla, world No 109, broke back immediately and both players then held serve without facing any further trouble to bring up a first set tiebreak which Federer dominated to take the initiative. "I wish I could play more matches, but nothing really worries me".
Roger Federer, who must win a record-extending 10th title in Halle to remain at the top of the world rankings, saved two match points to avoid an upset against France's Benoit Paire and reach the quarter-finals of the Halle Open.
Saudi Arabia vs Egypt: Record-breaking keeper saves penalty, but Pharaohs sink
Egypt goalkeeper Essam El Hadary , the oldest in World Cup history, deflects and saves a penalty shot from Saudi Arabia . Salah is also clearly not fully fit, but managed to score two goals in his two appearances, one from the penalty spot.
Federer revealed a trade secret when he suggested he gets extra energy once he makes the semi-final at a tournament as he knows he will play a maximum of two matches if results go his way. The Aussie double-faulted to hand over four set points but one was enough as Federer hit a backhand service return victor.
The nine-time champion produced an indifferent display at times but found his best tennis at the pivotal moments to beat the American qualifier 7-6 [7-1] 7-5 to reach a 12th Halle final. In front of a packed crowd under the roof in Germany, Federer finished with a flourish to break Ebden for a third time in the match and secure progress.
"At the same time, you need to show a reaction, try to break back".
Federer, 36, saved five break points in the second set before breaking in the 11th game.