St Helens coach Nathan Brown accused his players of complacency after needing a second-half fightback to overcome Hull.
Saints scored five tries after the break as they overturned a 10-6 deficit to maintain their winning start in the First Utility Super League with a 34-22 victory at Langtree Park.
Brown said: "To end up getting the result was pleasing but the first half was not where it needs to be.
"Our attitude was not very good. The way it looked to me was we thought we were going to go out there after a good win last week and things were going to happen.
"But if you don't do the hard, tough things early you have a chance of coming unstuck."
Brown said it was "probably not best to talk" about what he said to the players at half-time but paid tribute to them for turning the situation around.
He said: "I think the players understood what they did in the first half was not acceptable.
"They are a great bunch of guys, all hard workers. They knew what they tossed up wasn't good enough.
"You have got to make it hard for the opposition and we made it far too easy."
Saints turned the game around with tries from Sia Soliola, Jonny Lomax and James Roby - his second of the night - early in the second half before Tommy Makinson and Mark Percival made victory safe.
Hull's scores came from Mickey Paea, Richard Whiting, Gareth Ellis and Danny Houghton.
Hull coach Lee Radford said: "We had some real smart game management and if we had continued to do that for long periods we would have been fine.
"But for whatever reason in the second half we went away from that.
"It was just poor game management from our supposedly smart players.
"We went into our shells a bit and came up with some really dumb errors coming out of our own end.
"We backed that up with some ill discipline and before we knew it we were camped on our own tryline for long periods.
"Against a quality side you can't do that.
"I'm disappointed we let this one slip but they are a fair side."
Radford added that prop Garreth Carvell would be sent for a scan on Monday after suffering ankle ligament damage.
Saints centre Jordan Turner was concussed after a collision with Ellis but Brown said he was fine after the game.
Brown concluded by wishing Saints' arch-rivals Wigan good luck in the World Club Challenge against Sydney Roosters.
He said: "My heart says Wigan. A lot of St Helens people won't like that but I want to see Wigan win - but my head tells me the Roosters might be a little bit classy."