Wigan Warriors head coach Shaun Wane said he was "gutted" with the way his side performed after Widnes ended their unbeaten start to the season.
After leading 8-0 at half-time, they could not prevent the Vikings securing their first victory at the DW Stadium since 2003 as they won 18-12.
It ended Wigan's 21-month unbeaten home record in Super League, with their previous loss coming in June 2014.
"They were the better team," Wane, 51, told BBC Radio Manchester.
"We were poor defensively in the second half and when you're playing the best team in the competition you can't do that.
"I'm really gutted with the way we performed and I think we've cheaply given away our record at home, it's very disappointing."
Wigan had won their five previous league games to start the season, but are third in the table after the defeat, two points behind top-of-the-table Widnes.
"The review will be easy. It's really straightforward now as we need to fix it," added Wane. "What better game have we got to fix it, but St Helens away.
"Wigan against Saints derby, wherever we are in the competition, there is always that spice but respect there so it is a great game for us to come back on."