Cape Town - The Crusaders kept their Super Rugby playoff hopes alive with a tension-charged 28-21 win over the Chiefs in Hamilton on Friday.

The Crusaders leapt out to a 20-6 lead 20 minutes into the game but were reeled in by the hosts and forced to defend grimly in the final minutes to secure the valuable win in a frenetic atmosphere at a packed Waikato Stadium.

Trailing by a converted try, the Chiefs won two penalties after the siren as they hammered the Crusaders defence in a desperate bid to cobble a draw, but were denied when inside centre Sonny Bill Williams was held up on the line.

While Williams might regret not passing out wide to the right where the Chiefs had a three-man overlap, the Crusaders were deserving victors despite having the benefit of a controversial 52nd-minute try awarded by television review.

The win gave the Crusaders valuable breathing space in the wildcard berths for the playoffs, while the Chiefs have already sewn up the New Zealand conference and will contest the postseason.

Number eight Kieran Read gave the Crusaders the early running with a try in the first 10 minutes and flyhalf Dan Carter slotted the conversion and a drop goal minutes later.

Luke Romano capitalised on some clever work by scrumhalf Andy Ellis who dribbled a kick into his path at the left corner allowing the lock to cross for the Crusaders' second try in the 20th minute.

The Chiefs backs found their line, however, and scrumhalf Tawera Kerr-Barlow popped up a perfectly weighted pass two metres out from the line that towering lock Brodie Retallick swooped on and barged over for their first try.

Cruden put the Chiefs within four points at half-time but missed a penalty shot four minutes after the break to release the pressure.

The Chiefs were stunned minutes later when Ellis, brought down short of the line by a Kerr-Barlow tackle, was awarded a try after a lengthy video review.

The hosts re-gathered, however, as Williams, having been subdued all night, made a brilliant cameo appearance to plant the ball over the line after rolling over a pile of tacklers.

Dan Carter shrugged off a couple of earlier misses to slot a penalty and give the Crusaders a seven-point buffer with 18 minutes to play.

The Chiefs were denied a try on video review six minutes later, when wing Asaeli Tikoirotuma was judged to have planted the ball a fraction too wide at the right corner as he was brought down in a tackle.

The Crusaders called on their formidable defence to close out the match as they consigned the Chiefs to only their third loss of the season.

Teams:

Chiefs:
15. Robbie Robinson, 14. Tim Nanai-Williams, 13. Andrew Horrell, 12. Sonny Bill Williams, 11. Asaeli Tikoirotuma, 10. Aaron Cruden, 9. Tawera Kerr-Barlow, 8. Alex Bradley, 7. Sam Cane, 6. Liam Messam, 5. Brodie Retallick, 4. Craig Clarke (Captain), 3. Ben Tameifuna, 2. Mahonri Schwalger, 1. Sona Taumalolo

Substitutes: 16. Hikawera Elliott, 17. Toby Smith, 18. Romana Graham, 19. Tanerau Latimer, 20. Brendon Leonard, 21. Jackson Willison, 22. Lelia Masaga

Crusaders:
15. Israel Dagg, 14. Adam Whitelock, 13. Robert Fruean, 12. Ryan Crotty, 11. Zac Guildford, 10. Dan Carter, 9. Andy Ellis, 8. Kieran Read, 7. Richie McCaw (Captain), 6. George Whitelock, 5. Sam Whitelock, 4. Luke Romano, 3. Owen Franks, 2. Corey Flynn, 1. Ben Franks

Substitutes: 16. Quentin MacDonald, 17. Wyatt Crockett, 18. Tom Donnelly, 19. Matt Todd, 20. Willi Heinz, 21. Tom Taylor, 22. Sean Maitland