Martin O'Neill has backed his squad's efforts so far ahead of Saturday's trip to Manchester City.
Sunderland head into the weekend alongside City and leaders Chelsea as the only remaining unbeaten teams in the Barclays Premier League.
The Black Cats have claimed a win and four draws from their opening five games, representing a solid start to the new campaign.
And O'Neill says his players have given everything in difficult circumstances as he prepares for this weekend's game.
"We've had a tough time since the start of the season, playing tough opposition," he said.
"After Saturday, we will have played six games and four of those will have been away from home.
"I'm delighted with the team. They have been putting heart and soul into these games and we can improve."
Sunderland claimed a 3-3 draw at the Etihad Stadium last season and led with just a handful of minutes to go before City pulled level.
And O'Neill, whose side also beat the eventual champions on home turf, has pledged to attack again this time around.
"We've seen recently that better teams than us have played and for one reason or another have been forced back in games, to their detriment," he said.
"Of course, we want to stay as positive as we possibly can. We have to go and attack; we can't sit back.
"If we did that for say, half the game, Man City would be too strong for us.
"We are capable of attacking, I think there will be space for us and we have the players to cause them problems."
The game also sees the return of Adam Johnson to his former club after the winger made the move to the north west on transfer deadline day.
The winger won the Barclays Premier League with City last season and made 97 appearances in all following a £7m move from Middlesbrough.
Asked if he felt Johnson had a point to prove, O'Neill said: "I think we always have points to prove in this game, whether as players or managers.