Jack Ross felt his Sunderland side looked a 'little bit leggy' for the first time this season in the 1-1 FA Cup second round clash at Walsall.
Sunderland took the lead through Aiden McGeady's close-range finish but the Black Cats were pegged back second half, Newcastle United fan Andy Cook fired home the equaliser for the Saddlers.
The replay will take place a week on Tuesday with the draw for the FA Cup third round taking place Monday evening.
Sunderland have already played 19 league games, three Checkatrade Trophy games, a League Cup match and two FA Cup games this season, a heavy and demanding schedule, which will inevitably take its toll, especially with regulars George Honeyman and Chris Maguire missing today through injury.
Reflecting on the game, Ross said: “I wouldn’t have taken the result at half-time but the way the second half panned out, we would probably have taken it.
“We looked for the first time this season a little bit leggy.
“It is maybe understandable given the challenges we have had today, mentally and physically.
“I am pleased we can continue this run and we are in the draw, I was disappointed with aspects of the performance in the second half.
“The way the game panned out, it had a very different feel to it today.
“First half was almost too straightforward for us, we were very dominant, very different to how we expected the game to be like.
“We didn’t respond to the challenge second half but I will defend my players because of the demands of late, today was the first day it caught up with them a bit.”