UPDATE 1-Tennis-Federer serves up dominant first-round win against Istomin
Federer will play British qualifier Dan Evans, ranked 189 in the world, in the second round.
"I think I can trust my second serve in particular; when you trust your second serve, you can go after your first serve," Federer told journalists.
"I started to feel that midway through the first set it was going to be difficult for Denis to get into my service games. That relaxes you from the baseline. Then good things really happen."
Both players had their share of momentum in the largely baseline affair. Federer, however, did not face a single break point during the match, such was his serving dominance.
Federer broke Istomin's serve once in each set.
After a conservative first set, Federer tickled the giddy crowd with an on-the-run, curling backhand pass in the third game of the second set which seemed to add rocket fuel to his groundstrokes for the remainder of the match.
The Swiss broke serve that game and Istomin never recovered.
Federer and rival Novak Djokovic are both in search of a record seventh Australian Open title in Melbourne and, with it, a winner's purse of A$4.1 million ($2.96 million). (Reporting by Jonathan Barrett; Editing by Christian Radnedge and Clare Fallon)