LONDON (AFP) - Veteran striker Kevin Phillips came off the bench to score a superb extra-time penalty as Crystal Palace returned to the Premier League with a 1-0 win over Watford in the Championship play-off final on Monday.

Phillips, 39, struck mid-way through extra time on a sun-splashed day at Wembley Stadium, after Manchester United-bound winger Wilfried Zaha had drawn a tired foul from Watford right-back Marco Cassetti.

The Championship play-off final is said to be the richest game in world football and promotion to the English elite will reportedly swell Palace's revenue by up to £120 million (S$228.6 million).

"We're in the Premier League now, so God help us," said Palace manager Ian Holloway, who was appearing in his third play-off final in four years.

"It's absolutely massive for the club and I'm delighted for everyone connected. I feel very privileged." Palace last played in the Premier League in 2005, the last of four single-season stints in the top flight, and join Cardiff City and Hull City in graduating from the Championship this term.

Phillips, who began his career at Watford, said he was yet to decide whether or not to play on next season.

"To come on and get the winning goal against the club where it all started is a fairytale," said the on-loan Blackpool striker, who had tasted defeat in three previous play-off finals.

"If that is my last game, what a way to sign off. I'm going to have a break now. Every bit of my body is aching. I'll see what the future brings."

Zaha was a torment to the Watford defence throughout a scrappy game and will now link up with United, in a move that could be worth up to £15 million, having fulfilled his ambition of guiding Palace to promotion.

"I'm exhausted and speechless. It's a dream come true," he said.

"This is a all I wanted, leaving Palace knowing they are in the Premier League." Watford coach Gianfranco Zola, the former Chelsea star, was gracious in defeat.

"It has been a great season for us as we have done something not many people expected," he said.

"Games like this are very much on the day, and the better team was Crystal Palace." A crowd of 82,025 turned out for the final game of the English season, with Real Madrid coach Jose Mourinho among those in attendance, fuelling speculation that his return to Chelsea is now only a matter of time.

In a cautious first half, Zaha was the electrifying star turn.

He produced three dazzling runs down the right flank, the last of which culminated in a cut-back for Owen Garvan, whose shot was blocked.

By that stage Palace had already lost Kagisho Dikgacoi to an apparent calf injury, with Stuart O'Keefe coming on in his place.

It was not until the 57th minute that Watford substitute Alex Geijo produced the first shot on target, but as the game wore on, Palace began to turn the screw and Watford goalkeeper Manuel Almunia was called upon with steadily increasing frequency.

The former Arsenal player thwarted Palace on five occasions in the closing stages of normal time, saving from O'Keefe, Garvan and Aaron Wilbraham, twice, before plunging to his left to grasp a Mile Jedinak header in stoppage time.

Watford made the more enterprising start to extra time, Palace goalkeeper Julian Speroni superbly swatting the ball away from Troy Deeney, before Almunia's resistance finally gave way.

Zaha's dart into the box provoked a rash swipe from Cassetti and after referee Martin Atkinson pointed to the spot, Phillips swept an unerring penalty into the top-left corner.

Fernando Forestieri almost sent the game to penalties at the death, but although his shot beat Speroni, Joel Ward was on hand to head the ball off the line and safeguard Palace's return to the big time.