After initially signaling an improvement in results on Tyneside, Sissoko and his fellow January arrivals have come under criticism due to the Magpies' poor form, which has seen them win only one of their last five league games.
And with Alan Pardew's side sitting perilously close to the relegation zone in 17th, Sissoko has challenged his teammates to turn things around.
"As professionals we need to go out in the next game and show a different side to the one we did against Liverpool," he told the Sun.
"I'm proud to be a Newcastle player, and I want to do my best everytime I play for the club."
Newcastle travel to West Ham on Saturday in need of a vast improvement, with only four five points separating them and Wigan in 18th, who have a game in hand.
Although they are not in danger just yet, Sissoko knows that if their form continues until the end of the season, they may well find themselves facing Championship football next season.
"After a heavy defeat it hurts, especially when it is at home," he added.
"We'll go to West Ham and give 100% and, and hopefully, get the win."