Mark Skaife holds the record of most wins through 14 races, winning 11 of the first 14 in 2002.
In 2019, van Gisbergen's contemporary Scott McLaughlin won 10 of the first 14 races.
Van Gisbergen's 221-point margin marks the biggest series lead through five events since 2011, when Whincup opened up a huge 262-point gap on his closest rival.
Whincup won five races and added four more podiums in the first 11 races of the 2011 season across the opening five rounds.
Only five times has the series leader after five rounds failed to win the title.
Under the 300-point system, it happened on the very first attempt; Mark Winterbottom led eventual champion Whincup by 62 points.
Whincup was also 10 points down on Will Davison in 2012, and was a staggering 213 points down on Winterbottom in 2014.
Van Gisbergen was 86 points off Winterbottom in 2016, with Whincup a miserly four points off the lead in 2017.
Whincup and van Gisbergen are the only two drivers to lead by over 200 points after five rounds.
The next biggest lead belonged to McLaughlin last year, when he enjoyed a 177-point lead over Whincup.
Series leads after five rounds (under 300-point scoring system)
2008: Winterbottom led Tander by 52 points (Whincup 3rd, 62 points behind) 2009: Whincup led Davison by 144 points 2010: Whincup led Courtney by 24 points 2011: Whincup led Lowndes by 262 points 2012: Davison led Whincup by 10 points 2013: Whincup led Lowndes by 142 points 2014: Winterbottom led Lowndes by 101 points (Whincup 4th, 213 points behind) 2015: Winterbottom led Lowndes by 95 points 2016: Winterbottom led McLaughlin by 27 points (van Gisbergen 5th, 86 points behind) 2017: Coulthard led Whincup by 4 points 2018: McLaughlin led van Gisbergen by 158 points 2019: McLaughlin led Coulthard by 142 points 2020: McLaughlin led Whincup by 177 points 2021: van Gisbergen leads Whincup by 221 points
However, with the upcoming Townsville event to feature to 250km, 150-point races, van Gisbergen's big lead could be ruined in a heartbeat.
Should he fail to score in the opening race, and with a victory to Whincup, the gap could be cut to 71 points.
Van Gisbergen hasn't had a lead smaller than 100 points since he left Sandown in March, where he clean-swept the event.
2021 points lead progression
Race 1: van Gisbergen led Mostert by 12 points Race 2: van Gisbergen led Mostert by 33 points Race 3: van Gisbergen led Mostert by 60 points Race 4: van Gisbergen led Mostert by 80 points Race 5: van Gisbergen led Whincup by 150 points Race 6: van Gisbergen led Whincup by 153 points Race 7: van Gisbergen led Whincup by 145 points Race 8: van Gisbergen led Whincup by 139 points Race 9: van Gisbergen led Whincup by 140 points Race 10: van Gisbergen led Whincup by 178 points Race 11: van Gisbergen led Whincup by 190 points Race 12: van Gisbergen led Whincup by 193 points Race 13: van Gisbergen led Whincup by 207 points Race 14: van Gisbergen leads Whincup by 221 points
Only twice in 2021 has van Gisbergen finished a race with a reduced points margin, and both happened on the same day.
On the Sunday in Tasmania, Whincup beat van Gisbergen to the Race 7 win, before Whincup finished fifth to van Gisbergen's sixth in Race 8.
Whincup finished ahead of van Gisbergen in the Darwin opener, but the series leader extended his lead with his fastest lap bonus points.