Arsene Wenger admits Sunderland pushed his Arsenal side all the way as they bid to win the FA Cup for a third straight year.
Arsenal are strong favourites to hold the trophy aloft again come May.
And they safely made it through to the fourth round of the competition with the 3-1 win over the Black Cats.
But they were made to work for it.
Jeremain Lens gave Sunderland an early lead at the Emirates Stadium, taking advantage of mistakes from Kieran Gibbs and Laurent Koscielny.
But the Black Cats couldn't hold out and Arsenal slowly worked their way through the gears with Joel Campbell equalising in the 26th minute.
Second half goals from sub Aaron Ramsey and Olivier Giroud sealed a 3-1 win to ensure their safe passage into the fourth round of the competition.
Wenger: "We had to work but when you play a Premier League team that is normal.
"We had a very convincing second half and took over more as the game wore on.
"First half we were a bit shocked by being 1-0 down, it took us a while to find our game.
"After that, slowly, in the second half we took over and played in their half and scored great goals and created many chances."
Wenger, who made five changes to his Arsenal side, insists Arsenal will be giving it everything to make it three straight wins in the competition.
He added: "We have a desire to do well in this competition and to try and win it.
"There is a long way to go, you need a long run."
Arsenal youngsters Hector Bellerin - who set up both second half goals - Campbell and Alex Iwobi all impressed against Sunderland.
Wenger added: "I liked the timing of his passes [Iwobi], that is a vital quality and he plays forward and sees and is not scared to take people on.
"For a young boy, that is not easy.
"Bellerin had a good game and got stronger and stronger. In the last 20 minutes everytime he went forward he created a goal chance.
"I don't know [if there is a better right back in the country]. Look at the numbers though, the offensive and the defensive numbers.
"He is only 20 years old, there is a lot more to come from him."
Arsenal, who rested assist King Mesut Ozil, are not without their injury problems with Tomas Rosicky, Danny Welbeck, Alexis Sanchez and Jack Wilshere among their injured.
But Wenger is confident those players returning from injury - plus a new signing - will see them through the rest of the campaign.
Wenger added: "I believe that for us, the next step is to get Rosicky back, Wellbeck back, Sanchez back, Wilshere back. Maybe we get one player in.
"Overall, if we have no injuries I am not worried.
"If we have the same number of injuries, we are a bit short."