Toni Duggan rejoining the club from Atletico Madrid was a standout deal for Everton this summer - but boss Willie Kirk also brought in a host of other talent.
That included a club-record deal to sign Sweden international Hanna Bennison as well as landing three-time Serie A winner Aurora Galli.
Despite such outlays, Everton were humbled 4-0 by Manchester City at Goodison Park last Saturday.
Defending WSL champions Chelsea, who also lost their opener away at Arsenal, are next up and Blues boss Hayes is not expecting an easy ride.
"I think it was just a 10 to 15-minute period...the second half, I thought it was a much different game," she replied when asked what she made of Everton's defeat.
Asked if the Toffees should be aiming to put themselves in among the likes of Chelsea, Manchester City and Arsenal this season, Hayes added: "They'd hope so, especially the amount of money they've spent.
"I'm sure Willie will expect that of his group and I think you'll see that with the amount of football on show for everybody this year. I'm sure there will be some indifferent results throughout the season.
"Yes, of course Arsenal started the fastest, but we are one game in."
With just one game being played, Hayes is not one to panic at the fact her Chelsea side lost 3-2 at the Emirates Stadium last Sunday.
"As always they are a great group," she said of the mood in training this week.
"They're brilliant and it is just one game of the season, it's a long way to go. We have had really good sessions.
"It is great to have all the players back together in the last couple of weeks so (we are) just preparing as we normally would and just looking forward to being back with our home fans on Sunday."