By FOX Sports staff
Guidolin could only watch on from the sidelines as his team dominated the game before Juraj Kucka nodded the hosts ahead in the first half.
Adding to the feeling of frustration, Udinese then missed two good chances in stoppage time - through Mehdi Benatia and Alexander Merkel - to try and force a draw.
Instead, it left Davide Ballardini to pick up his second win since replacing Luigi Del Neri as Genoa boss.
"I am happy with the performance, I am sorry for the score," Guidolin said on the club's website.
He added: "We deserved something more, but we didn't make it".
Guidolin also had praise for his opponent Genoa.
"Genoa are a concrete, organized, well-built team, Ballardini did a very good job in short time. This squad never missed quality and now is tonic, concrete and well-organized," he said.
Prior to Sunday's defeat, Udinese had won four games from six to finally reach seventh spot last week.
They now drop back down to ninth place with 36 points from 25 games.