The Nigeria international, who has scored 14 league goals this season, scored the winner in the FA Cup tie against Nottingham Forest after coming on as a second-half substitute on Saturday.
Ighalo continues to be linked with a possible Vicarage Road exit but Guedioura expects him to stay put in Hertfordshire and help Quique Sanchez Flores' side build on their promising first half of the season
"I think the statistics speak for themselves," said Guedioura after the FA Cup win.
"He only came on for a few minutes and scored. He is an amazing player. He is a top, top player for the Premier League - not just for our team.
"It is really important he is staying. If you remove Ighalo it is 60 or 70 per cent fewer goals. I want him to finish the season with a lot more goals and why not be the top scorer in the league?"