Joe Westerman's impressive hat-trick rubber-stamped Castleford Tigers' Super League play-off spot and all but ensures Harlequins will not make it.

The two sides began the day with just two points between them but Westerman's heroics left Quins to wonder what might have been.

Mitchell Sargent and Dean Widders were also among the scorers but it was Westerman who stole the show.

The Tigers were rewarded for their early pressure after 16 minutes when stand-off Westerman went at full stretch for his sixth converted try of the season.

Westerman then doubled the lead just three minutes later with a run through the Quins pack for a converted try.

Quins started to have more of the possession, but were unable to find their way through a dogged Castleford back-line - so much so that their play was characterised by unforced handling errors.

Any hopes for the hosts of a quick comeback were dashed just three minutes after the restart, when centre Kirk Dixon powered his way over the try line down the right flank to effectively seal the victory for Tigers. Westerman's kick once again was successfully converted.

James Evans further compounded Quins' misery just three minutes later when he drove down low.

Westerman missed his first conversion of the day but the 19-year-old made amends after 52 minutes with yet another converted try at full stretch.

Castleford compounded Quins' pain four minutes later when Widders took advantage of Rangi Chase's sprint down the centre.

There was a sense of inevitability about Castleford's next try, when Liam Higgins scored his second of the season with a run from the centre after 62 minutes. This time, Kirk Dixon converted.

Dixon handled yet another score for the Tigers after holding onto a short kick towards the right flank with 15 minutes left.

With Brett Ferres touching down on the left flank on the final hooter, Castleford booked their place in the play-offs with some gusto.