The Hornets took the lead inside 90 seconds at St. James' Park, as Will Hughes capitalised on a unfortunate United deflection to open the scoring for Javi Gracia's side.
However, Newcastle forced their way back into the Premier League clash, with Fabian Schär levelling before the half-time whistle, with Hayden meeting Emil Krafth's cross from the right flank before the ball dropped kindly into the path of the Swiss defender.
But, despite the large spells of attacking pressure from the hosts in the second half, Steve Bruce's side were forced to settle for one point.
Hayden told nufc.co.uk: "It's hard to tell at the minute if it's two points dropped. We've had a lot of chances. I thought it was a good game with a lot of a chances at both ends of the pitch. I thought we had the better of them and if we were more clinical, we could have taken the three points.
"They're a good side. Their position in the table is a bit false and they've just had a bad start. A point can't be knocked at this stage of the season. Every point is important.
"Obviously, we were going for the three points and you could see that on the pitch, giving everything to go forward and to press and score that goal but sometimes in these games you look back and think it's a good point.
After a slow start from the Magpies, Hayden was pleased with the spirited response from his side and almost marked his milestone of appearances with a rare goal.
The 24-year-old's ferocious long range strike in front of the Gallowgate End forced Watford goalkeeper Ben Foster into expertly tipping the goal bound effort over the crossbar.
He added: "It was a bit of a fluke much like the goal we conceded midweek. There's been a deflection, fallen to the player and he's taken the chance from six yards out. I thought it was a credit to the lads for rallying round and produce the goal before half-time to put the tie level and give us the platform to go in the second half. I thought we came out and we started with more intensity and played a lot better.
"Ben Foster came to me after the game and told me he didn't know how he managed to save it! The ball was moving all over the place and it was a very good save. It wasn't meant to be but you could see every single player was giving everything.
"To play 100 games for this club is no mean feat. I'm proud of that and I hope I can continue to make an impact on the team, progressing in my own personal performances which can, in turn, helps the team to progress.
With the international break taking place next week, the Magpies will wait a fortnight before their next Premier League contest, an away trip to Champions League holders Liverpool.
And while Hayden believes the break may have halted United's momentum, the central midfielder admitted it would be beneficial for numerous squad members in their bids to recover from injuries.
"I feel it has possibly come at the right time," Hayden said. "There are arguments to and for. I think we could have got the momentum after a good week. We beat Spurs and, taking away penalties, we drew with a Premier League side in Leicester and have drawn this weekend when we should have possibly won. It's been good in terms of that on the back of the defeat against Norwich.
"Then again, we have a lot of injuries in the camp and players carrying knocks so it will give them that bit of time to get a bit more of the squad back and push for the next batch of games.
"It's about resting and recovering now. The lads going away on international duty will have to do their thing for the countries. Those who are not is just about resting and it gives you that period to work on things you might not work on when everyone is there.
"The individual sessions give you that chance to work that little bit harder because you're not going to be doing the same sessions. I'm looking forward to it and it will be a chance for me to improve yet again."