Pietro Ghersi in Alfa Romeo at Monza, probably in 1933.  One guess then, is the XI Italian Grand Prix on 10 September 1933 where Ghersi had entry #42 and rode an Alfa Romeo 8C 2300 Monza and ended in 7th place. According to <a class="external autonumber" href="https://en.wikipedia.org/wiki/Pietro_Ghersi">[1]</a>, he entered for his own racing team "Pietro Ghersi racing team" (Scuderia Ghersi?). A bit odd then, that the Scuderia Ferrari emblem can be seen (the prancing horse). He did not participate at Monza in 1934, when he actually was member of this team, so ... bit unclear.
Unknown photographer
<a rel="nofollow" class="external autonumber" href="https://www.facebook.com/SupercarsSalvatMX/posts/483247628851462">[2]</a>