A much improved second-half performance was not enough to earn London Welsh a bonus point as Exeter Chiefs completed a league double over them at Old Deer Park.

The visitors crossed from three first-half tries only for Welsh to conjure two second-half scores from Greg Evans to set up a barnstorming finish with both sides chasing a bonus point.

It was Exeter who grabbed it, deep into injury time, when fly-half Tony Yapp touched down to crown a fine personal performance which brought him 16 points.

Yapp opened his account when Welsh were penalised at a scrum in front of their own posts, and the Exeter fly-half had no trouble in bisecting the uprights.

Welsh were showing plenty of ambition with the ball in hand, but it was through their pack that they nearly hit back. Matthew Jones fired a penalty into the corner, only for Exeter to drive Welsh into touch with the line in sight.

Against the run of play it was Exeter that increased their lead; Jason Luff, the Exiles' tormentor-in-chief when the two sides met at Sandy Park in October, cut a beautiful line through the Welsh defence.

The wing couldn't quite finish off what he'd started, but with numbers out wide, John Andress found a gap in the stretched Welsh line to touchdown.

Although whether the prop dropped the ball as he attempted to ground it, was open to debate.

With their confidence up, Exeter upped the pace and for a moment Welsh appeared to be teetering on the edge, but an eight-minute stoppage for a leg injury to Andress disrupted the tempo of the game, and ended with the prop been stretchered from the field.

As the first-half slipped into added time, Welsh then suffered a decisive double blow as the visitors ran in two quick tries.

Wing Josh Drauniniu rounded off a breakout from Exeter's own 22; a move instigated by centre pairing Ali Fatialofa and Wade Kelly.

And immediately from the restart Fatialofa and Kelly again combined to release Drauniniu, only to this time see the pacey wing hauled down just short.

However, from the resulting scrum, No9 Clive Stuart-Smith dived over, with Yapp converting both scores to give the visitors a seemingly unassailable 24-point cushion at the break.

The Chiefs had lead Coventry by the same margin at the interval the previous week in the Cup, only to fail to register a single point in the second-half, but there seemed little chance of history repeating itself as Exeter proceeded to set up base camp five-metres from the Welsh line.

But the Chiefs, so clinical when given a sniff of the Welsh line in the first 40, got themselves bogged down and Mark Lee lead the Welsh breakout as he scooped up loose ball and countered with the aid of Evans. With Robert Jewell, a half-time replacement for Henry Barrett, moving into the centres, Evans switched to the wing and it was a reshuffle that would eventually pay dividends for Welsh.

In the short-term however, it was now the turn of Welsh to enjoy the territorial upper hand, but without the reward. Welsh were now bossing the scrums, and the penalty count was rising against the Exeter front row, allowing Jones to pepper the corners. And it was Jones who finally found the key to unlock the Exeter rearguard, as his precision cross field kick picked out Evans on the run, and he beat the last man and score in the right hand corner.

Although the former Ospreys man couldn't add the conversion, it was his angled kick that took Welsh back into the Chief's 22. Paul Cox's charge up the middle sucked in the Exeter defenders, and quick ball saw Jones' miss pass picked out replacement hooker Alex Walker, and he delivered the scoring pass for Evans to dive over in the same corner for his and Welsh's second. This time Jones added the extra two-points and Welsh had their own bonus-point score to aim for.

However, as the game opened up and the home side threw caution to the wind it was Yapp who had the final word, as he popped up in the right place to collect the final pass and saunter round underneath the posts to secure Exeter their fourth try.

London Welsh: P Sampson, J Strong, G Evans, P Mackey, H Barrett (R Jewell h-t), M Jones, A Chilten (G Nicholls 60min), P Doran Jones (C Beech h-t), A Kwasnicki (A Walker 46min), A Liffchak, W Lewaravu, M Corker, J Mills (captain), M Lee (K Burke 763min), H Jenkins (P Cox h-t).