Key props up Kent with mammoth 261
Kent 424 v Durham
Kent captain Robert Key scored the third double century of his first-class career to ensure fellow County Championship strugglers Durham endured a tough opening day in Canterbury.
The 31-year-old former Test batsman maintained his concentration levels despite short breaks for rain either side of lunch and throughout four excellent spells from former England team-mate Steve Harmison to make 261.
Without his knock - which included 38 fours and three sixes across six hours at the crease - Kent would have struggled but instead made 424 all out by stumps.
The right-handed opener, who came into the game with a paltry championship average of 14.3 this season, featured in century stands for the third and fifth wickets and hardly played a false shot during his 270-ball stay.
His only fortunate boundary came from a top-edged pull that sailed over the keeper's head against Harmison who, with 4 for 52, was easily the pick of Durham's injury-hit attack.
"It was good fun and a long time due," said Key, after missing out on a career-best score by only 10 runs. "After the poor start I've had to the season I probably owe the team some runs and it's nice to get a decent score under my belt."
Batting first after winning the toss, Key lost opening partner Joe Denly to only the sixth ball of the day from Harmison, caught behind without scoring when fishing at a legcutter. Then, in Harmison's next over, Geraint Jones fenced away from his body to steer a catch to Michael Di Venuto at second slip to make it 10 for 2.
Martin van Jaarsveld helped Key see off Harmison's first spell after which Kent's third-wicket partners began to take the initiative, posting 117 in 25 overs either side of lunch while Durham used seven bowlers in a bid to stem the flow.
Van Jaarsveld (30) went five balls after the re-start when his leaden-footed drive against Harmison was snaffled at the second attempt by Dale Benkenstein at slip. Then, four overs later, Sam Northeast became Harmison's fourth victim after nicking another leg-cutter to new Durham captain Phil Mustard.
Key moved to his first century of the summer from 105 balls and found another willing ally in Azhar Mahmood (43) to take Kent to their first batting point with a partnership of 106 in 23 overs. They were only two short of equalling Kent's fifth-wicket record against Durham when Mahmood edged to slip off Benkenstein.
Useful contributions from Alex Blake (31) and Rob Ferley (19) helped Key bat on past tea and pass Ed Smith's 175 scored at the Riverside in 2000 - the previous best by a Kent batsman against Durham.
Key posted his second double hundred for Kent inside 10 months from 223 balls and with 30 fours, but soon after Durham's Chris Rushworth nipped out Ferley and Simon Cook in the space of three deliveries with the second new ball.
Typically, Key countered by hooking the same bowler for a brace of sixes but Rushworth should have had his man caught at midwicket for 233. Benkenstein inexplicably downed a sitter, allowing Key to plunder 18 from the over.
The Kent opener fell in the final over of the day only 15 shy of the ground record score by a Kent batsman when he was bowled around his legs by Ben Harmison attempting an audacious clip to fine leg.