"We were a yard off the pace in the first half and allowed them to get on top," said Owls manager Brian Laws. "It was a mistake by our keeper who rushed out and left Hasselbaink with an easy finish that has cost us.

"We created more in the second half, but failed to make their keeper work and we do not seem to have the consistency we need up front."

Hasselbaink was on hand to finish off Gavin Rae's finely-crafted pass in the 35th minute to leave Wednesday languishing just one point above the relegation zone.

Owls boss Laws had made two changes to the side that earned an FA Cup replay with Derby. Leon Clarke and Steve Watson came in for Francis Jeffers and Jermaine Johnson and newcomer Ronnie Wallwork was on the bench.

The home team were quick to attack and Peter Whittingham, Hasselbaink and Stephen McPhail all fired in shots.

The Owls began to settle, but even so Cardiff were unlucky not to open the scoring when centre-back Roger Johnson hit a post. However, they did grab the lead two minutes later when Hasselbaink used all his predatory instincts to latch on to Rae's through-ball before firing home.

Laws introduced Wallwork after the interval in an attempt to bring his side back into the game, but five minutes after the restart Glenn Loovens went close to doubling the home side's lead, but hit a post.

Cardiff's aerial threat troubled the visitors all game and Paul Parry outjumped his marker and his header was saved by Grant.

The visitors refused to give up and there was almost a debut goal for Wallwork, but his 73rd-minute header was clawed out from underneath the bar by Oakes.

The visitors pressed for a late equaliser, but substitute Deon Burton had an effort at goal which flew wide.

Cardiff City: Oakes, McNaughton, Capaldi, Loovens, Johnson, Rae, Whittingham, McPhail, Ledley, Parry, Hasselbaink (Thompson 79). Unused substitutes: Enckelman, Purse, MacLean, Ramsey.

Sheffield Wednesday: Grant, Bullen, Hinds, Beevers, Spurr, Whelan, O'Brien, Esajas (Johnson 40), Watson (Wallwork 46), Tudgay, Clarke (Burton 75).Unused substitutes: Wood, Small.

Referee: A Woolmer (Northamptonshire).