A try from reserve forward John Ulugia four minutes from time thwarted a gutsy Chiefs fightback to secure a 25-20 win for the Waratahs in Sydney that opens up both the Vodacom Super Rugby overall log race and the New Zealand conference.
The Blues are now the frontrunners in the Kiwi conference following a second consecutive defeat for a Chiefs side that started poorly before building momentum later on.
The Brumbies are still top of the log ahead of their big derby against the Reds, but the overall log table, with teams who have fewer points than others placed higher because of the conference system, is horribly confusing.
The Waratahs led 15-0 in Sydney and were full value for that lead, but the Chiefs had almost all the momentum in the second half and had even snatched an unlikely lead eight minutes from the end through a try from massive 130kg prop Ben Tameifuna as he swiveled over from a loose scrum in front of the posts.
The Gareth Anscombe conversion made it 20-18 as the Chiefs went ahead for the first time in the match and they would probably have won had they opted to kick a penalty to the touchline.
Instead they opted to give Charlie Ngatai a long-range attempt at posts from 55 metres. He was short with the kick, which gifted possession to the Waratahs, and a great response from the hosts saw them sweep upfield and onto the attack.
Ulugia received the ball in the backs with the impressive presence of Israel Folua on his shoulder, and perhaps the Chiefs' defence were duped into thinking it would be the dangerous fullback who would carry the ball forward.
Whatever the reason, the gap opened up for the Ulugia, who went through to score with no-one in front of him. McKibbin converted and that was the ball game.
The Waratahs went ahead as early as the third minute of the game, a big run from prop Benn Robinson creating the pressure on the Chiefs inside their own 22 that led to the penalty that McKibbin kicked to make it 3-0.
There were a lot of early mistakes from the Chiefs, who looked half asleep and looked to be finding each other in the combinations after a few changes had been made since the defeat to the Reds.
One of the men left out, Gareth Anscombe, joined the fray fairly early and was to prove one of the best Chiefs players on the night.
Early mistakes cost the Chiefs, none more so than the fumble that led to a Waratahs attacking scrum on the quarter-hour mark.
Good scrum ball was spun to Adam Ashley-Cooper who made the thrust that created the space for Cam Crawford to score in the right corner to make it 8-0.
There was some impressive work at the breakdown from the Waratahs, but perhaps their most valuable player on the night was Folua, who showed again why he was given such a high rating prior to him joining the Waratahs from Rugby League.
His try in the 38th minute, with the Waratahs player soaring up to take a cross kick and fall over for the try between the attentions of two Chiefs defenders, was one of the most spectacular of the season.
He was also impressive in a defensive role, winning the battle in the air against the Chiefs when they tried the same thing that had netted the Folua try earlier, and then he was the man who shepherded Anscombe towards touch before scragging him when the Chiefs’ replacement fullback had made an impressive break and appeared to have the tryline almost at his mercy.
Anscombe missed a penalty on the halftime hooter to complete a miserable first half for the Chiefs, but their luck changed three minutes after the restart when Waratahs lock Sitaleki Timani was yellow-carded for a dangerous tackle.
It was while the Waratahs were down to 14 men that the momentum shifted comprehensively in the Chiefs’ favour, with Anscombe scoring four minutes later as he switched inside to score near the posts after Aaron Cruden had taken the ball over the gainline on the blindside.
Anscombe’s conversion made it 15-7 but four minutes later McKibbin restored some balance with a penalty to stretch the home team’s lead to 11.
Then came a long period of Chiefs territorial ascendancy, and twice they were over the line only to be held up. The Tameifuna try appeared to have ended the frustration, only for Ulugia, and the Waratahs, to have the last laugh.
Waratahs – Tries: Cam Crawford, Israel Folau, John Ulugia. Conversions: Brendan McKibbin (2). Penalties: McKibbin (2).
Chiefs– Tries: Gareth Anscombe, Ben Tameifuna. Conversions: Anscombe (2). Penalties: Anscombe (2).