Inverness boss Terry Butcher hailed the 4-0 win at Tannadice as the best performance in his time at the club.
"It was very enjoyable to watch and hopefully the fans and players will get confidence from this," he said.
"For me, the most important thing was getting the ball down and passing and we created a lot of chances.
"I don't want to get carried away because it's early in the season but, wow, if the players can play like that, who knows?"
Butcher joined Caley Thistle in January 2009 but could not prevent the Highlanders from dropping out of the Scottish Premier League.
However, he oversaw an immediate return to the top flight with an unbeaten run of 22 games clinching the First Division title last term.
"It's wonderful to be back in the SPL and we're enjoying it," added Butcher, who saw his side lose out to Celtic on the opening day of the season.
Inverness opened the scoring against Dundee United with a fabulous long-range effort from Kevin McCann and added three more goals after the interval.
Adam Rooney bagged a brace, with one coming from the penalty spot, and Russell Duncan scored with a sublime chip from distance.
"We wanted a good second display after not really turning up against Celtic last week," explained former England captain Butcher.
"We knew United would throw everything at us but the players were very determined to combat that.
"Playing on the break suits us as well. Inverness have got a good record away from home.
"A lot of people have asked if Adam Rooney can reproduce his First Division form in the SPL and I think he showed he's definitely there.
"He's a different player from when he left the SPL. The confidence factor is enormous and he has a great deal of belief in his own ability."
Source: BBC Sport
Source: BBC Sport