Sussex collapsed on the last morning at Hove as an innings-and-two-run defeat to Warwickshire increased the threat of relegation to the second tier of the LV County Championship for Michael Yardy's side.

Former Derbyshire pair Ant Botha and Boyd Rankin shared seven wickets in 12 overs as the hosts crumbled from 133 for three to 172 all out.

Botha took five for 51 - his first five-for for Warwickshire - in a victory which not only killed off the Bears' relegation fears but even triggered hopes of a surprise late tilt at finishing as runners-up.

Sussex, meanwhile, must lift themselves quickly for a crucial relegation battle with Yorkshire at Hove next week.

They resumed on the final morning at 113 for three, still needing 61 to avoid an innings defeat. It was Botha, whose long economical spell on the previous day forced Sussex into virtual inertia, who struck the early blows.

The left-armer struck twice in six balls. Nightwatchman James Kirtley attempted an ambitious force off the back foot and fell lbw. Carl Hopkinson, having scored just a single, was completely bamboozled by an arm-ball and perished the same way.

That left Sussex still 37 behind with five wickets in hand and their hole became much deeper when Rankin struck twice in five balls.

The Irishman, who began the day with figures of 1-1-0-1, having disposed of Murray Goodwin the previous night, added two huge wickets in five balls. First he ended Andrew Hodd's 202 minutes of admirable resistance at 33 (168 balls, four fours) when the wicketkeeper fenced outside off-stump and Jonathan Trott took a low catch at first slip. Then the dangerous Dwayne Smith, having announced himself with a savage pull for four, nicked a superb delivery to wicketkeeper Tim Ambrose.

That left Ed Joyce, batting down the order as he had not fielded due to a hip injury, as the last specialist batsman. But Sussex's hopes of heroics from the first-innings centurion came to nothing when he played back to Botha and the spinner won his third lbw decision in four overs.

Piyush Chawla lifted Botha for a huge straight six but it proved an isolated blow of resistance. The Indian leaned forward to the next ball and bat-padded to Ian Westwood at short-leg.

When Ollie Rayner was out in almost identical fashion, Botha had figures of 36-15-51-5 and the Sussex inquest, which must surely be deep and frank, could begin.