"I am worried. We have to think game by game but we have to improve because these are more difficult games," Guidolin told British media.
"I am worried about the lack of chances because if we play this way it is difficult to win in the Premier League."
The Italian denied reports of disagreements with his players after he singled out South Korean Ki Sung-yueng who refused to shake his hand having been substituted against Southampton.
"This is not a good attitude. I have to speak with him," Guidolin said.
"There is no problem with the respect between me and the players. In this league and this squad I have found good guys, good players with a good relationship," he added.
Swansea are 15th in the table.
(Reporting by Nivedita Shankar in Bengaluru, editing by Ed Osmond)
