Karanka’s side are top of the table going into this lunchtime’s huge Championship summit meeting, with the Basque believing that Boro’s first 45 minutes in the 1-1 draw with the Hornets earlier this term was his side’s best showing of the campaign.
He said: “It was a game we should have won, but it was the best half that we have played all season.
“(Today) will be difficult. They are having a good season. They have good players, particularly up front. They have a good manager and a good team and it was important we won against Wigan on Friday.”
The game represents yet another top-of-the-table battle with Boro, who have recently faced Ipswich and Bournemouth, also tackling Norwich City a week on Friday.
Karanka added: “This game is very important. You don’t want to lose because if you don’t it’s three points they don’t have, which is just as important now.
“Our performances weren’t good over a period as we had a lot of games and no time to prepare.
“Now we are fresh. We’ve had two good weeks which were important and now we will go to Watford feeling good.
“I made a mistake when I thought it would be Derby and Bournemouth and us fighting it out at the top. We are in a very good position, but we have six games now which are very important.”
Boro are one point clear of Bournemouth, who entertain Birmingham City today.
Last six: Watford WDWWLD; Middlesbrough WLWWLW.
Referee: M Jones (Cheshire).
Last time: Watford 1 Middlesbrough 0; February 15, 2014; Championship.