The Hornets take on Leicester City on Saturday as the Premier League returns for the first time in three months.
"They're a very good side as you could see today, they set up very well positionally and tactically and showed they're a very good team," Welbeck told the club website.
"They beat Arsenal the other day and then they've come here today, but we've got a good result and it's something we're now looking to build upon."
On his own return from injury, Welbeck added: "It was good to get the minutes under the belt and mostly just everyone's getting ready for the game next week.
"This period has been a bit shorter than a normal pre-season but it's been pretty long if you take everything into account with training at home and trying to do as much as possible to keep the fitness as high as possible.
"It's very weird being at the stadium and not having fans there. Ever since you've been playing football you've always had a crowd there. It's a strange situation but it's one we've got to deal with. We've got to come to terms with it as a team and as a club in general.
"Everyone's doing it so it's not just us, everyone's in the same boat so we're going to try to deal with it as best as possible, even though when you're at home you want to have the fans there with you. But it's something we've got to deal with.
"We know how important these games are coming up so we're going to give it our best shot. Going into each and every single game we want to give it our best and get the points."