Story (based on the memoirs of another pilot, never officially confirmed):

Baciu was an ace with ten victories (in the Romanian system, a multi-engined plane is worth multiple victories). On 4th May 1945, he and Of. Ech. Ioan Milu, 3rd highest-scoring ace of the Romanian Air Force, both part of 1st Fighter Group, were out on a regular combat sortie over northern Hungary. 

On their way back to base, they encountered a formation of USAF P-51D Mustangs. Seeing their allies fly by, the Messerschmitt pilots waved their wings in greetings, and the American pilots responded by doing the same. A few moments after, the Romanian pilots encountered a formation of Il-2 Sturmovik's and their Yak-3 escort going the opposite direction. Again, the Romanian waved their wings at their allies, but this time to no response. 

Or, rather, not the expected response. Two of the Yak-3's broke off and opened fire on Baciu and Milu. The latter, who was credited with over 24 Soviet aircraft shot down before the change of sides, dove away in hope of outrunning the Soviets. He was caught and crash-landed in Austria. 

Baciu, on the other hand, accepeted the challenge and fought the Yak pilots. He allegedly managed to shoot one down before being shot down himself. He crash landed near Kromeriz. He apparently counted over a dozen bullet holes on his aircraft (including from cannon fire).

The victory was swept under the rug as although the Romanians and Soviets had little sympathy for one another, they were officially allies and the Soviets had the future of Romania within their hands. Records only indicate that Baciu and Milu crash-landed without further explanation. 

Although Baciu was lucky enough to survive the war, his luck didn't last long. He was murdered shortly after the war by an armed thug while delivering mail with his Po-2 biplane. So he never really got to tell the story himself.

Source: "Rumanian Aces of World War 2" by Denes Bernad, pp. 67-68.

I don't know much about Baciu's "Red 8". It is clearly an early Bf-109G-6 with short tail and bird-cage canopy. There is no visible German-language stencils painted on the plane, indicating it was probably refurbished and repainted in a Romanian workshop. It is definitely not a Romanian-built Bf-109Ga-6, as those had tear-drop-shaped MG bulges on the cowling, as opposed to the round one on German machines (note: the first Ga-6 made in Romania had German-style bulges, but that plane, serial 315, had distinctive IAR camouflage and number 315 on its tail section). So I think it was definitely an overhauled German-delivered G-6 repainted in Romania using RLM colors. 

Dumitru Baciu and his Bf-109G-6 "Red 8", late Spring 1945. On 4th May 1945, he allegedly scored the last aerial victory of the (Royal) Romanian Air Force.