Wasps failed to overcome the absence of their senior coaching team of Ian McGeechan and Shaun Edwards as Worcester fly-half Willie Walker clinched a dramatic 13-12 win for Worcester with a last-minute drop goal at Sixways.

Walker struck with just 49 seconds left on the clock to deny Wasps their first league win at the stadium.

Little went right for Wasps on a miserable afternoon as McGeechan, their director of rugby, and Edwards, the club's head coach and Wales' defence coach, were both stranded in Paris after encountering problems in getting back from France's RBS 6 Nations win over the Welsh on Friday night.

That left assistant coach Liam Holden and part-time coach Tony Hanks in charge and Wasps had to contend with further logistical difficulties caused by problems with their team coach which delayed their arrival until just 40 minutes before kick-off.

It was hardly ideal preparation and Wasps struggled for fluency against a side low on confidence after conceding 13 tries in their previous three games.

This time Worcester kept their line intact, thanks to a superb display from rookie centre Alex Grove, and they kept their composure in a frenetic finale to set up the position from which Walker, on loan from Gloucester, was able to seal a dramatic win.

Worcester had their own pre-match problems to deal with as former Australia full-back Chris Latham failed a late fitness test on a toe injury, and Wasps were quicker to settle with Danny Cipriani giving them the lead with a sixth-minute penalty.

Worcester, who spent the first 15 minutes camped in their own 22, required a crunching tackle on Josh Lewsey from Grove, making the first Guinness Premiership start of his career, to deny Wasps a try.

Wasps did increase their lead when Cipriani landed his second penalty, via the crossbar, although it proved short-lived.

Grove latched onto a flick-pass from Mark van Gisbergen and raced 40 metres to score the opening try and Walker tagged on the conversion to give Worcester the lead.

Wasps were soon back in front when Cipriani slotted his third penalty but they failed to turn further pressure into points as Van Gisbergen had a try disallowed for a forward pass and Lewsey then lost possession as he went for the line.

Cipriani was also narrowly off target with a penalty attempt which brought the first half to a close, and it was Worcester who regained the lead when Serge Betsen was penalised for killing the ball in a ruck and Walker slotted the penalty.

But Cipriani found the target again when referee Martin Fox spotted former Wales centre Hal Luscombe handling back in a ruck.

Worcester's victory hopes appeared to have gone when Walker was unable to land a 70th-minute penalty after Wasps were again penalised at the breakdown.

But Worcester captain Pat Sanderson galvanised his side for one last effort and Walker found the target to secure their first league win in more than three months.