Wellington conceded a try in the opening minute at Ballymore before rallying to beat the Queensland Reds 24-10, and the Cats, last year's wooden-spooners, upset the Bulls 23-17 in Johannesburg.
At Canberra, Scott Fava crossed twice in the second half, while Radike Samo and Gene Fairbanks scored a try apiece as the Brumbies gained a bonus point for scoring four tries to grab a share of the competition lead with the neighboring New South Wales Waratahs.
The Waratahs beat last season's semifinalist Waikato 25-7 in Sydney on Friday, while Auckland and the Stormers also notched victories on the 2005 tournament's opening night.
The Brumbies went into Saturday's match without playmaker Matt Giteau, who broke his hand in a trial match.
The backline stocks were further eroded with the loss of two Australia internationals -- Mortlock limping off in the 19th minute with suspected knee ligament damage, and Rathbone helped from the field just before halftime after a head knock.
The Crusaders led 10-6 on tries from Casey Laulala and Andrew Mehrtens before the Brumbies rallied just before halftime. Three minutes before the interval and with Crusaders hooker Corey Flynn in the sinbin, Samo scored off a pass from Wallaby captain George Gregan.
Fava and Fairbanks -- Giteau's replacement in the Brumbies' backline -- secured the bonus point with three tries in the second half.
Mortlock will undergo tests today to determine the extent of his injured knee.
Tana Umaga's Hurricanes withstood the Queensland Reds, outscoring the home team at Ballymore in the last quarter and thriving on a glut of turnovers.
Scrumhalf Piri Weepu took the kicking duties from Jimmy Gopperth in the second half and landed two late penalties before setting up a last-minute try for winger Lome Fa'atau against the wilting Reds.
The hosts scored in the opening minute via Australia vice-captain Elton Flatley, but conceded 22 turnovers in the first tackle and were outmuscled at the breakdowns by the bustling Hurricanes.
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