Stefano Okaka's move to Watford was not one of the most heralded of last summer's transfers. But he belatedly announced his arrival in style yesterday, scoring twice on only his second start in the Premier League.

After Romelu Lukaku had put Everton ahead, Okaka volleyed a stylish equaliser and he headed his second to give Watford a 3-1 lead soon after Sebastian Prodl had put the Hornets ahead for the first time.

The much-travelled Italy striker began his career with Roma and had played for three other clubs and been loaned to a further four – including Fulham – before moving to Vicarage Road from Anderlecht in August for an undisclosed fee.

After suffering a hamstring injury on his first appearance, as a substitute in Watford's 4-2 win at West Ham, he was sidelined for six weeks. But with Troy Deeney misfiring in the search for his 100th Watford goal, Okaka's impact here was very welcome.

Lukaku opened the scoring, taking advantage of some poor Watford defending (Getty)

But Everton's decline continues. After they began the season with four wins and a draw in their first five games, it seemed that new manager Ronald Koeman had woken one of the Premier League's slumbering giants. But they have won only one of their past ten league matches and allowed Watford to wrest control of this game from them far too easily.

Watford seemed able to mount attacks largely unopposed for long periods and although Lukaku's second goal five minutes from time gave Everton hopes of rescuing a draw, Koeman would not have been fooled into believing that all was well again even if they had managed it.

The game began with some energetic but random attacking, the most dangerous effort a misdirected cross by Gerard Deulofeu that veered closer to goal than he intended, forcing Heurelho Gomes into a volleyball-style fisted clearance.

Okaka's sublime finish left Stekelenburg helpless (Getty)

Even when Everton took the lead in the 17th minute there seemed an element of fortune to it as Gareth Barry, facing away from goal and without looking up, scooped the ball over the Watford defence. But Lukaku had read it well and was already a stride ahead of Miguel Britos, half-volleying colly under Gomes.

It was the Belgium striker's eighth league goal of the season but his first for five games and he celebrated by holding up one finger on one hand and four on the other to represent the number 14 shirt of teammate Yannick Bolasie, who will miss the rest of the season with a knee injury.

Deeney had an excellent chance to reach his century when Nordin Amrabaat forced his way past Ramiro Funes Mori on the right and crossed low but the Watford striker chose to take a touch rather than shoot first time and his control let him down.

But when Amrabat created another opening on 36 minutes, it was taken. Deeney nodded a long clearance back to Okaka, who passed out to the right. Amrabat crossed to the near post, where Okaka charged forward and stole two yards on Ashley Williams, backheeling the ball past Maarten Stekelenburg on the volley.

Prodl put Watford ahead, heading home from a free-kick (Getty)

Sebastian Prodl nodded too high from a free kick on the right by Adlene Guediora in the 56th minute but he did better three minutes later. This time the free kick was taken by Jose Holebas on the left and the Austrian defender escaped his markers to head home.

It was nearly three soon after when Britos, unmarked, had his diving header dramatically parried away for a corner by Stekelenburg. But then it was three in the 64th minute as Okaka again showed his knack of getting away from defenders, charging to the near post to meet Holebas's corner with a glancing header that Leighton Baines was unable to keep out.

Everton still had 25 minutes in which to try to get back into the match, but they were unable to muster anything more than rudimentary attacks until substitute Aaron Lennon's cross found Lukaku in the 85th minute and his header left Gomes motionless. Lukaku's driven cross then slipped through Gomes' fingers but no Everton player was close enough to profit.

Deeney was full of praise for his strike partner. "The big man did fantastic today and it was only his second start. We have a real powerhouse, the two of us together will cause problems.

"I'm desperate for a goal but I'm not desperate to take it off someone else. We've been working hard at set pieces. Mine will come, it is the team that mattered.

"It's been tough, we were poor against Stoke, West Brom was strange as we got done by two set pieces. It's just the rub of the green but a win is a win and it is good to beat teams around us."

Watford (4-1-3-2): Gomes; Zuniga (Kabasele 90), Prodl, Britos, Holebas; Behrami; Amrabat, Guediora (Janmaat 61), Capoue; Deeney, Okaka (Watson 81).

Subs not used: Pantilimon, Success, Sinclair, Ighalo.

Everton (4-2-3-1): Stekelenburg; Coleman, Williams, Funes Mori, Baines (Lennon 83); Gueye (Barkley 64), Barry; Deulofeu, McCarthy, Mirallas (Valencia 71); Lukaku.

Subs not used: Robles, Jagielka, Cleverley, Holgate.

Referee: Anthony Taylor