Guessand entered the match in the 72nd minute as a substitute, replacing Chadi Riad. By this point Wolves had been reduced to ten men after a red card but were still holding onto their clean sheet.
But the Frenchman provided the match-winning goal in the 90th minute, firing home after Tyrick Mitchell's low cross.
And the man of the moment was full of praise for the home support for their backing on what was, at times, a frustrating afternoon.
"Today we fought for this win," Guessand told Palace TV. "I think we deserved to win today, even after a long time without a victory.
"But let's keep pushing now, because I think with the quality we have in this team, from the keeper to the striker, we can do something good.
"I thought the team showed really good determination to keep pushing and be patient. Because sometimes you can be a bit lazy after a red card [for the opposition], but we kept pushing.
"Every time they [the supporters] are here supporting us, we feel it. We felt it today. We felt again the support of our fans and that was really important."