Although Cavendish has a healthy lead over Spain's Jose Joaquin Rojas and Belgium's Philippe Gilbert with one sprint stage remaining - Sunday on the Champs-Elysees in Paris - he will not ease up, given his recent history.
The bitter memory of losing to Thor Hushovd two years ago means Cavendish will be constantly looking over his shoulder in the Alps later this week, where he expects rivals to try for gain bonus points to close the gap.
"Two years ago I thought I had the green jersey, Thor went on the attack in the mountains, got it back," Cavendish said. "I was disqualified from the stage and I lost a lot of points. Nothing's guaranteed."
Cavendish is 37 points ahead of Rojas, and 71 clear of Gilbert heading into Tuesday's 16th stage.
But Cavendish is wary that both are better climbers than him, and can close the gap during the intermediate sprints in the Alps. Tuesday's stage is also a medium-mountain trek where Gilbert could punish him by launching an uphill attack, then three even tougher high-mountain stages follow.
"The battle's not over until we cross the line in the Champs-Elysees," Cavendish said. "I know Gilbert is quite far back but he desperately wants this jersey. He's an incredibly talented bike rider, he'll find some ways to get points back off me. He can maybe get points where I can't."
Cavendish has won a formidable 19 Tour stages in his career, but never the green jersey. He lost to Italian Alessandro Petacchi by 11 points last year, and by 10 points to Hushovd of Norway in 2009.
His HTC-Highroad know exactly how badly Cavendish wants to finally win it.
"It must mean something, he's had green socks on for a year or two," Australian Matt Goss said. "It would be massive for him having been so close a couple of times and winning the amount of stages. He's got to be hungry for it now."
Most sprinters don't come close to getting 19 stage wins in their entire career, but the 26-year-old Cavendish has several more years to keep piling them up.
"If he wins 5 stages (a year), he's got 50 up his sleeve," Goss said.
Cavendish has carved out a reputation as an explosive sprinter of unmatched brute force, but also as one of sport's most outspoken athletes.
He pulls no punches with his uncensored outbursts, or his comments about other riders.
Cavendish feuded with Germany's Andre Greipel when they rode for HTC-Highroad last year, and was very critical of Hushovd during the 2009 Tour. This year, he launched a tirade at a journalist for several minutes at a press conference.
"We know Cav, he's explosive and at the same time he's a really nice guy. You have to know him," Eisel said. "I've spent most of the time with him. I don't know how many days a year but it's at least 250, so I know him. He has a big heart, but also a big mouth."
On stage 3 of this Tour, Cavendish was disqualified from an intermediate sprint because officials ruled he used his head to push Hushovd - who was also disqualified.
"The thing that gets you most about the Tour is the mental stress," Cavendish said. "The mental fatigue just drains you."
After winning Sunday's 15th stage, Cavendish moaned about Tour contenders like Cadel Evans and Ivan Basso jostling for position near the front - where there is less chance of getting caught in a pileup.
"Every single day (when there is) even a little bluster of wind, every GC rider is trying to be up there," Cavendish said. "I'm fighting with Cadel, I'm fighting with the Schlecks, I'm fighting with Basso in the last kilometres. It's really stressful."
