Mikhalkin isn't a bad opponent by anyone's standards. He was the one to finally pop Oosthuizen's cherry, and has wins over Ngumbu (x3), Kasperski, Chioui, and only ever lost to Kuziemski years back. He's alright. Lateral step from Shab at worst.
Or Gvozdyk, who has been the WBO number one for several months, and really should have had the opportunity to compete for the vacant strap....?