Resurgent Queensland Reds defended magnificently to defeat Jaguares 18-7 in Argentina and record three consecutive Super Rugby victories for the first time in five years.
Earlier on Saturday, reigning champions Canterbury Crusaders suffered back-to-back losses for the first time in three years after going down 25-17 to Otago Highlanders in Dunedin.
There were also wins for the ACT Brumbies, Western Stormers and Golden Lions, who held off a brave attempt by the Tokyo-based Sunwolves to win on the road the first time since their 2016 debut with a 40-38 win in Johannesburg.
After conceding 45 points in the season opener to the Rebels the Reds -- under new coach and former All Black Brad Thorn -- have beaten the Brumbies, Northern Bulls and Jaguares.
"We defended very well," said skipper James Slipper after the Buenos Aires triumph in which the Reds did not concede a point for 73 minutes after Bautista Delguy's early try.
"We tested ourselves and came up trumps. The forwards did very well in the set pieces. We are going to enjoy this win as it is the first away from home for a long time," added the Wallaby loosehead prop."
"Our opponents defended superbly during a second half in which I believed we should have scored several tries," conceded Jaguares skipper, flanker Pablo Matera.
Forced to play inside their own 22 for much of the second half after leading 11-7 at half-time, the Reds embodied the dogged refusal to submit that Thorn showed so often for New Zealand.
The crucial second Reds try came seven minutes after half-time when a move that originated deep in their half ended with Filipo Daugunu brushing off Delguy to cross the line.
James Tuttle converted and the Jaguares camped in Reds' territory without finding the key to unlock the Australian defence.
- Crusaders lose again -
The three conference leaders are the Melbourne Rebels in Australia, Highlanders in New Zealand and Lions in South Africa.
Highlanders faced record eight-time champions Crusaders and the match lived up to its high-profile billing with a couple of late Lima Sopoaga penalties ensuring victory for the 2015 title-winners.
Crusaders, who fell to 2016 champions Wellington Hurricanes last weekend, had narrowed the gap to two points before the accuracy of the England-bound fly-half took the game away from them.
"It was a hell of a game. We knew it was going to go down to the wire," said Highlanders skipper and All Black Ben Smith.
After conceding 94 points away to the Lions a year ago, and 50 at the Coastal Sharks last weekend, the Sunwolves must have feared the worst at Ellis Park.
But they led 31-26 on the hour before tries from Springbok hooker and 2017 South African Rugby Player of the Year Malcolm Marx and Rohan Janse van Rensburg rescued the hosts.
"This was a game we really wanted to win, but my team were not good enough. We will keep trying," promised Sunwolves skipper Yutaka Nagare.
- Stormers off sick bed -
Many Stormers barely trained during the week because of 'flu, but they recovered sufficiently to overcome Auckland Blues 37-20 in Cape Town.
Young South African fly-half Damian Willemse was a worthy man-of-the-match award winner after succeeding with his seven shots at goal, and EW Viljoen scored two tries.
"It was a great team performance," said Willemse. "Many of us battled with illness during the week, but we gave our all today."
Former champions Brumbies recovered from two consecutive defeats run by overcoming the Sharks 24-17 in Canberra with Wharenui Hawera slotting four penalties, including two from beyond 50 metres.
It was a disappointing start for the Sharks on a tour that includes matches against the in-form Rebels, Blues and Hurricanes.
"The Sharks are a quality side and in good form too so it's nice to get a win at home," Brumbies skipper Christian Leali'ifano said.