The BetVictor Welsh Open is at the business end with only four players left to battle it out this weekend in Cardiff.

In stark contrast to the German Masters earlier in February, where there were no top 16 players featuring in the semi-finals, this week’s ranking event has seen a resurgence in the elite with only top 10 ranked competitors left in the draw.

Ronnie O’Sullivan continues to be the overwhelming favourite to land his fourth Welsh Open crown after yet another dominant display to knock out old rival Mark Selby.

The world no.1 actually appeared to start well by winning the opening frame but, after O’Sullivan levelled with a 93, any chance Selby had seemed to evaporate in the third frame with a costly miscalculation in the points.

O’Sullivan, seemingly buoyed by Ding Junhui’s earlier 147 break against Neil Robertson, was on course to compile a maximum of his own with the reds perfectly spread but missed a routine black off the spot on 57.

With the black now safe, Selby replied by taking pinks and blues with the remaining reds but didn’t tally enough to avoid having to pot the tricky final black.

After a brief tactical battle, O’Sullivan superbly potted it and never looked back, punishing every Selby mistake with further breaks of 61, 75 and 132 to complete a 5-1 rout.

The ‘Rocket’ will face Joe Perry in the last four after the latter also secured a 5-1 success over last year’s runner-up Ben Woollaston.

Perry has himself played well this week but will need to raise his game significantly if he is to challenge the 40 year-old on current form.

In fact, if O’Sullivan maintains his level it is difficult to see how anybody can threaten his tilt at the title in the Motorpoint Arena.

Not even Australia’s Robertson, who didn’t let Ding’s heroics distract him en route to a 5-2 success over the Chinese.

Robertson has been the form man in the last few months, emerging victorious in both the Champion of Champions and the UK Championship at the tale end of 2015, so he does seem like the man capable of denying O’Sullivan.

First, though, the 34 year-old must tackle a determined Mark Allen, who went out to prove some doubters wrong in his 5-0 demolition of home hope Michael White.

The Northern Irishman was seemingly upset at recent comments made by Steve Davis that the two-time ranking event winner was a Championship player, rather than of Premiership quality, and duly took it out on White.

Robertson and Allen have had many important battles down through the years but the Melbourne man has a clearly favourable record, including a triumph in the final in Coventry last November.

Yet, one would expect there to be more chance of Allen upsetting the odds and reaching the final than of Perry achieving the feat.

Time will tell, and with the semi-final encounters increased to best-of 11, there is more opportunity for twists and turns to ensue.

Click here to view the draw.