[9] In 2009, Sadauskas won his first ever individual title at the Conference USA Championships in Houston, Texas, posting a time of 0:44:18 sec.

At the 2009 FINA World Championships in Rome, Italy, Sadauskas represented Lithuania and placed 36th in the 100 m Freestyle event.

Besides that, Sadauskas set an individual-split time of 48.90 seconds, and a national record of 3:16.47, along with his teammates Vytautas Janušaitis, Paulius Viktoravičius, and Mindaugas Margis, in the men's 400 m freestyle relay at the 2009 FINA World Championships in Rome, Italy.

At the 2011 FINA World Championships in Shanghai, China, Sadauskas placed 29th in the 100 m Freestyle event with the time 0:49:66 sec.

Sadauskas represented Lithuania and Southern Methodist University at the XXVI Universiade Games in Shenzhen, China.

Sadauskas qualified for the men's 100 m freestyle at the 2012 Summer Olympics in London, by breaking a meet record and eclipsing a FINA B-standard entry time of 49.54 seconds from the Open Luxembourg Nationals in Luxembourg City.. At the 2012 Summer Olympics, he challenged seven other Olympians in the fifth heat, including three-time Olympian and UC Berkeley graduate Dominik Meichtry of Switzerland.

[6] Sadauskas also raced at the Arena Grand Prix Mesa, Arizona, where he finished 4th in the 100 m Freestyle with a time of 0:49:78 sec.

Besides that, Sadauskas and his teammates Danas Rapsys, Giedrius Titenis and Tadas Duskinas participated in the 400 Medley Relay where they placed 13th with a new national record of 3:36:72.

At the 2013 LEN European Short Course Championship in Herning, Denmark, Sadauskas and his teammates Danas Rapsys, Giedrius Titenis and Tadas Duskinas were 4th in the 200Medley Relay with a time of 1:35:26sec.

[4] Sadauskas competed at the International de Canet-en-Roussillon Meet, Canet-En-Rousillon, France, where he was 8th in the 100 m Freestyle event with a time of 0:49:54 seconds.

[15] At the FINA 16th World Championship in Kazan, Russia, Sadauskas and his Lithuanian teammates Danas Rapsys, Giedrius Titenis and Tadas Duskinas made 2016 Summer Olympics qualification standard.

[3] At the 2015 LEN European Championship in Netanya, Israel, Sadauskas surprised Lithuania and the world with a new Lithuanian national record in the 100 m Freestyle event, which was 21-years-old.