Eighth-seeded Finn Nieminen defeated Germany's Tobias Kamke 6-3 6-4 and will play either Kevin Anderson or former world number one Lleyton Hewitt in the second round.
Sixth seed Youzhny defeated America's Brian Baker 6-3 6-1 and Gael Monfils could await if the Frenchman beats local wildcard Patrik Rosenholm.
The top four seeds receive byes into the second round with Jo-Wilfried Tsonga and Tomas Berdych leading the field.
At the ATP Moscow event it was a similar story with sixth seed Denis Istomin of Uzbekistan beating Bjoern Phau of Germany 5-7 7-5 6-1 and eighth seed Tatsuma Ito of Japan coming back to defeat Roberto Bautista-Agut of Spain 6-3 1-6 6-2.
The top seed in the Russian capital is Alexandr Dolgopolov.
A seed did drop in Vienna where sixth seed Robin Haase of the Netherlands was beaten 1-6 6-3 6-2 by Australian Marinko Matosevic.
Top seed in Austria is Juan Martin del Potro with Janko Tipsarevic also in the field as the pair look to clinch spots at the ATP Tour Finals in London.
ATP Stockholm results
8-Jarkko Nieminen (Finland) beat Tobias Kamke (Germany) 6-3 6-4
6-Mikhail Youzhny (Russia) beat Brian Baker (U.S.) 6-3 6-1
ATP Moscow results
Malek Jaziri (Tunisia) beat Rajeev Ram (U.S.) 6-3 6-1
8-Tatsuma Ito (Japan) beat Roberto Bautista (Spain) 6-3 1-6 6-2
6-Denis Istomin (Uzbekistan) beat Bjoern Phau (Germany) 5-7 7-5 6-1
Lukas Rosol (Czech Republic) beat Daniel Gimeno-Traver (Spain) 7-6(9) 7-6(2)
ATP Vienna results
Marinko Matosevic (Australia) beat 6-Robin Haase (Netherlands) 1-6 6-3 6-2
Gilles Muller (Luxembourg) beat Steve Darcis (Belgium) 6-7(3) 6-4 6-3