Essex are back in Division One of the LV County Championship after a six-year absence following a resounding five-wicket victory at Derby.

They chased down a target of 359 in 65 overs to steal the second promotion spot from Northamptonshire after Derbyshire had declared on 240 for four, with Garry Park scoring an unbeaten 103.

It seemed a generous declaration by the home side and that proved to be the case as Essex skipper Mark Pettini and Ryan ten Doeschate roared across the finishing line with five overs to spare.

The sixth-wicket pair added 156 in only 17 overs, with ten Doeschate demolishing Derbyshire's attack with a brilliant unbeaten 108 off only 59 balls.

Fittingly it was Pettini who hit the winning run to end on 85 not out and spark wild scenes of celebration in front of the Essex dressing room.

Northants are bound to be unhappy about Derbyshire's declaration but there can be no arguing with the quality of ten Doeschate's batting.

The Dutch all-rounder romped to his hundred, which included seven sixes and nine fours, from only 57 balls.

Derbyshire skipper Chris Rogers, whose own team's promotion hopes ended when Northants beat Leicestershire, defended his declaration.

He said: "We thought they would have struggled to get that if we bowled well but all credit to them, they batted fantastically.

"We wanted to come third and we needed some time to bowl them out."

Essex's fate had been in Derbyshire's hands at the start of the day with the home side leading by 221 with seven wickets intact.

Danish Kaneria was the visitors' biggest threat but Wavell Hinds drove him for two sixes before the leg spinner bowled him as he played back to one that hurried on.

But Essex soon turned to their part-time spinners to try to set up a run chase and Park filled his boots to score his second century of the season.

After reaching his half century from 120 balls with a six off Alastair Cook, he completed his second fifty from only 33.

Park and John Sadler took 78 off 13 overs from Cook and Pettini before Derbyshire surprisingly declared shortly before lunch, leaving Essex to score at 5.4 an over to win.

Cook got them off to a good start with 25 off 30 balls before he drove Jon Clare low to cover and Tom Westley followed his first innings hundred with another impressive display.

The 20-year-old played intelligently until he cut Graham Wagg's left-arm spin to backward point after scoring 40 off 41 balls, and John Maunders kept his team on course with 55.

Even so, the game was in the balance when James Foster skied a sweep to leave Essex on 203 for five in the 43rd over, but Pettini and ten Doeschate then ripped Derbyshire apart.

They went into the last hour needing 105 off 16 overs but they required only 11 of them as ten Doeschate engaged the turbo to bring joy to Essex and misery to Northants.