The overstated affair, held at the historic Rundale Palace, included a spectacular fireworks show while the walls of the baroque masterpiece were treated to vast projections of Magonis' beaming face.
However, despite the hubristic display, attention focused not on the birthday boy but on his impressive guest list which included Economy Minister Dana Reizniece-Ozola, Transport Minister Anrijs Matiss and former Foreign Minister and Transport Minister Aivis Ronis.
But the real center of attention was Yakunin, banned from entering the United States as part of US sanctions against Russia following its invasion and annexation of Ukraine.
A long-time associate of Putin from his KGB days, Yakunin is also board member of the 'Russkiy Mir' organization which plays a key role in Russia's propaganda efforts overseas.
Yakunin was placed on the US blacklist in March 2014 but was omitted from the European Union's similar blacklist after Latvia lobbied strongly to have his name removed.
Economy Minister Ozola-Reizniece said she was attending as the spouse of her husband Andris Ozols, head of the Latvian Investment and Development Agency.
"It's up to the person celebrating to decide who they invite. I was invited along with my husband. It's not up to me to decide who is invited and who is not," Ozola-Reizniece told De Facto.
Alongside Yakunin were other senior Russian Railways figures Boris Lapidus and Salman Babayev.
Transport Minister Anrijs Matiss told De Facto: "He [Yakunin] does not have any restrictions of movement in the European Union. He was at a private event in Latvia at the invitation of Magonis, I understand. Also, he will certainly be visiting other European Union member states...having such a personal connection to Magonis is a very positive sign."
Yakunin exerts considerable influence in the Baltic states, and not only because of the the key role logistics play in the local economies. In 2010 he was linked to efforts to bankroll the Center Party in Estonia.
Magonis has worked at Latvian Railways since 2003, and as president since 2005.
In 2013 he was awarded a state decoration, the 'Cross of Recognition' (motto: “Pour les honnêtes gens”/"For Honest People") by President Andris Berzins.