The Hornets took the lead through Heidur Helguson after just 19 minutes, and doubled his tally three minutes later. He was not greatly troubled by the Iron defence on either occasion.
Their third goal was also gifted to Watford, when a defensive mix-up gave the ball to Henri Lansbury – who was on loan at Glanford Park last season – who squared it for Danny Graham to score.
“The goals they gave away I am very disappointed with,” said Adkins
"We knew that Watford were a good side, very lively and industrious in the centre of the park and having Henri Lansbury with us last year, we knew that.
"We've come away from home to try and nullify that, and we did create chances, but if we can't defend a simple cross into the middle of the six-yard box then we're not going to win games of football, it's as simple as that."
Malky Mackay, the Watford manager, praised his strike pairing of Graham and Helguson.
"I know that he's going to cause problems for the centre-half and the partnership with him and Danny Graham, certainly caused people problems,” he said.
"I am delighted that Danny Graham got his goal because he's been working so hard every day in training and he worked so hard in games."