The third-placed Waratahs (39 points) face out-of-contention Reds in Brisbane wary of the major upset they nearly caused against the Crusaders.

The Hurricanes (40 points), who moved into second place behind the Crusaders (52 points) after their 21-10 win over the Force face the Blues in Auckland.

Like the Blues, the other contenders for the semis except the Crusaders, have to win well and rely on other results to favour them to be able to extend their season.

The Crusaders had to roll out their big guns despite an under-manned opponent to overcome the brave Reds 27-21.

Dan Carter celebrated his return from an ankle injury after six weeks with a try and two conversions.

The Crusaders scored 19 unanswered points in the last 13 minutes after trailing 8-21 to top the round-robin in 2008.

Carter came off the bench and immediately made his presence felt by converting replacement lock Ali Williams' try from near the touchline to put his team ahead with four minutes to go then dived over for a try to seal the win.

"With the injury and things I only started kicking again a week ago," Carter revealed later.

"It was just one of those things that the work I've done on the training pitch over the last few years (kicked in) and I didn't really lose too much."

The Hurricanes advanced with a clinical game against the Force as rain and swirling winds made conditions extremely difficult for both teams in Wellington on Friday.

They adopted a disciplined, structured approach to wear down the Force and score tries through Andrew Hore and Hosea Gear. Halfback Piri Weepu kicked three penalties and a conversion.

Nick Evans returned to his old stamping ground at Carisbrook in style, scoring the Blues first 21 points in their 40-15 win to keep their playoff hopes alive.

The former Otago and Highlanders first five-eighth, who announced earlier in the week that he was off to play for English club Harlequins at the end of this season, scored two tries and kicked three penalties and a conversion in their 26-3 halftime lead. He added another conversion before retiring in the last quarter.

The Blues took the wind out of the Highlanders by halftime with a strong scrum and by committing them to numerous tackles.

Halfback Taniela Moa serviced the backline efficiently and Blues turned the Highlanders constantly.

In other matches, a hat-trick of tries from flanker Jacques Botes kept the Sharks in the playoff race. They beat the Cheetahs 33-14 in Durban and the Bulls the Brumbies 28-17.