Championship wrap: Watford climb to second
With table-toppers Cardiff City not in action until Sunday, Watford made the most of Hull City's defeat at Bolton with another victory in front of their home fans at Vicarage Road.
Czech striker Matej Vydra – on loan from Udinese like many of Watford's players – continued his stunning season with the game's first goal after 35 minutes.
Swedish defender Joel Ekstrand, also at the club on a short-term basis from Udinese, doubled their advantage with 22 minutes remaining.
Jamie Ward's penalty for Derby gave the visitors a glimmer of hope but they were unable to find an equaliser as Watford extended their unbeaten run to five.
Hull City missed a chance to go within two points of Cardiff as they dropped to third following a 4-1 hammering at Bolton Wanderers.
Most of the damage was done in the first eight minutes as Darren Pratley, Mark Davies and Craig Dawson all scored early.
Irishman Robbie Brady netted a consolation in the second half for Hull but Dawson added a second to cap off a comprehensive win.
Fourth-placed Crystal Palace lost their first match in five at Sheffield Wednesday, who are now unbeaten in six.
Leroy Lita scored with nine minutes left for Wednesday who won 1-0 at Hillsborough.
Brighton and Hove Albion kept up their good form with a 1-0 home win over Burnley, which came thanks to David Lopez's goal, while Nottingham Forest posted a 2-0 triumph at Charlton Athletic.
Radoslaw Majewski and Henri Lansbury bagged the goals for Forest, who backed up last week's 6-1 thumping of Huddersfield Town with another impressive display.
Bristol City moved off the bottom of the Championship with a 5-3 home win over Barnsley that saw Peterborough United drop to the foot of the table.
Jon Stead bagged a brace inside the first hour while Liam Fontaine and Lewin Nyatanga also scored as Bristol kicked away to a 4-0 lead.
Substitute Chris O'Grady produced a response for Barnsley before Steve Davies wrapped up the win for the hosts.
Tomasz Cywka and Jason Scotland netted late consolations for Barnsley, who are just two points above the relegation zone.
Nikola Zigic and Chris Burke scored in Birmingham City's 2-0 win at Peterborough while Leeds United were held to a 0-0 draw at Blackburn Rovers.
Strugglers Huddersfield Town and Ipswich Town also played out a goalless stalemate, as did Blackpool and Leicester City.