Watford have confirmed the sale of Matej Vydra to Derby County following a 3-1 loss at home to Arsenal in the Premier League on Saturday.
Czech international Vydra was a key member of the team that saw Watford earn promotion to the top flight in 2014-15.
But he spent last season on loan in the Championship with Reading and will now return to the second tier with Derby, signing a four-year contract for an undisclosed fee.
Santi Cazorla's penalty, together with goals from Alexis Sanchez and Mesut Ozil, saw the Gunners record a simple win, Roberto Pereyra netting a consolation for Watford in the second half.
OFFICIAL: Matej Vydra signs a permanent deal with . Thanks for your efforts at , . August 27, 2016
"The second half we played good and should have scored more … some episodes in the game did not go in our favour," Watford manager Walter Mazzarri said.
"[Petr] Cech played incredible for them, saved a goal two or three times but I am very happy with how our team played.
"A lot of players are new so we have to prepare later. The organisational things are still missing … and this really didn't help."
