Harlequins director of rugby Conor O'Shea knows his team cannot afford another loss as they fight to make the top four in the Premiership.
Saturday's 23-9 win over London Irish kept the 2012 champions in the hunt, leaving them six points off fourth place.
Nick Evans scored 13 points including one of three tries for the hosts who welcomed back England internationals Mike Brown, Danny Care and Chris Robshaw.
"We know we have to win all four of our remaining games to be within a chance of finishing in the top four," said O'Shea.
"We know that whoever wins when we go to Sale is in the fight for the top four. Whoever loses, isn't.
"It's going to be a real fight and I've always said it will be. We want to fight until the bitter end.
"Everybody plays each other and we have Leicester and Bath to come here.
"You have to keep going, take it day by day and not look too far ahead."
O'Shea admitted that his side were far from perfect against the Exiles, only leading 10-9 at half-time but benefiting from the wind in the second half.
"The standards we set ourselves are better than that," stated O'Shea.
"We're never arrogant enough to take any Premiership win for granted, so we should be happy with the win, but our ambition and standards are higher.
"The breakdown was frustrating beyond comprehension throughout the game. We'll take the win, but we know there's more in this team."