Watford’s win over Newcastle United was the first win in the Premier League for Newcastle since the 1-0 win in October, and saw the Hornets reach the FA Cup semi-finals for the first time since 2003.
Watford are now unbeaten in nine league matches, their longest unbeaten run since a run of eight matches in 2014/15.
Away from the field, the Hornets lost defender Marco Pappa, who is out with a hip injury, and striker Marco Maggio.
They also lost their leading scorer, Moussa Sissoko, who will miss the second leg against Newcastle with a hamstring injury.
Newcastle, who were on the verge of winning the title when Watford took the lead, failed to register a single shot on target.
They had the ball at the back four and were able to play with pace and penetration, but Watford were able hold on.
Wes Morgan fired a shot straight at a stunned Ryan Giggs, but Giggs calmly handled it for the home side’s second goal.
Nathan Ake scored Newcastle’s third, after the Hornets had given away possession in the area.
But Newcastle’s defence was exposed.
Wembley’s top scorer, Ashley Williams, was sent off for a challenge with Watford goalkeeper Hugo Lloris, while Newcastle striker Moussa Dembele and goalkeeper Jordan Pickford both were yellow cards.
The Hornets, who won the Championship last season, lost the FA Youth Cup to Norwich City in the fourth round.
Wet-footed striker Ashley Williams has been sent off against Newcastle, and the Hornets are now on a five-match losing streak in the FAI Cup.