This has seen them slip to 18th in the League One table, and midfielder Russell believes it's time Pompey started bullying opponents.
"It is crucial we get back to basics and move forward - we have seven days to prepare for the next game and install an improved work ethic in the squad," he told the club's official website.
"Any run of defeats is going to hurt players. If you have a winning mentality then losing games is horrible.
"Fans can accept it if your passing is a little off-key and your touch is not there. But the ugly side of the game is crucial - we must get that right and start bullying teams.
"Hard work, tackling and passion are not hard to find if you have that inside of you. Once we do, I'm sure our quality will shine through."
