Argyle debutant Dan Grimshaw's early error gave Watford the lead - but he made amends with some excellent saves
Two goals from Mileta Rajovic ensured Watford reached the third round of the Carabao Cup for the first time in three years as they beat Plymouth Argyle 2-0 at Vicarage Road.
The Hornets took the lead when Rajovic's flicked finish snuck through the legs to Argyle's debutant goalkeeper Dan Grimshaw as they had the better of the first period.
Grimshaw made amends with a string of fine saves either side of the break as Watford continued to have the upper hand, but he was finally beaten when Rajovic volleyed in from eight yards inside the final 20 minutes.
Ryan Hardie hit the Watford post inside the final 10 minutes as Wayne Rooney's side struggled to create chances.
Grimshaw was one of nine Argyle changes as he and striker Michael Obafemi made their debuts.
But the former Blackpool stopper will not want to see the first goal he conceded for the Greens again. Watford's good build-up play down the right saw Ryan Porteous pull the ball back from the byeline to Rajovic, who clipped it through Grimshaw's hands and legs from close range and into the net.
Grimshaw made an excellent diving save from the unmarked Tom Ince 15 minutes later, who volleyed Rajovic's header across the box from eight yards.
Rajovic was denied by a good Kornel Szucs block seven minutes later, while Callum Wright had Argyle's first effort when his weak shot was easily saved after Matthew Sorinola had put him through on goal.
Grimshaw made another superb save early in the second period when Ken Sema's header looked destined for the bottom corner as Watford upped the pressure.
Substitute Rocco Vata's low strike was well saved by Grimshaw midway through the second half, before Grimshaw's finest stop of the night as he denied Rajovic from close range after an excellent cross from James Morris.
But Grimshaw could do little to keep out Rajovic's second asthe striker held off Szucs after a Porteous header had been flicked into the air by Julio Pleguezuelo.
Hardie struck the post as he pounced on a weak Ryan Andrews backpass in a rare foray in the Watford 18-yard box.
Vata then somehow failed to get a third for Watford deep in stoppage time as he side-footed wide when unmarked at the back post with the goal gaping.
