“I hate to fail,’’ he said. “You know I celebrate victories, but failing is something that tears me up.’’

So when Hendrick signed Dale Earnhardt Jr. to a five-year contract extension Sept. 1, assuring that the 36-year-old namesake of the late seven-time NASCAR champion would remain at Hendrick Motorsports through 2017, failure was not an option.

The deal, which sprouted from a handshake agreement made earlier in the season, reaffirmed the vow Hendrick made in 2007 when he first signed Earnhardt and promised to spare no cost or resource in helping him achieve his championship aspirations.

“I was going to run for Rick, and how I ran with Rick would likely define my career as a racecar driver,’’ said Earnhardt as he relaxed in the lounge of the No. 88 team’s hauler Friday during a break from his preparations for today’s Sylvania 300 at New Hampshire Motor Speedway, the second stop in the Chase for the Sprint Cup Championship.

“It’s been disappointing at times, but we’ve also had some pretty good times,’’ Earnhardt said of a career in which he has recorded 18 victories - including the 2004 Daytona 500 - and finished fifth in the two Chase appearances he made for Dale Earnhardt Inc. “We’ve got an opportunity to keep trying to improve and we’ve got an opportunity to do better, and that’s all I want.’’

When he left DEI to drive for Hendrick Motorsports after a contract dispute with his stepmother, Teresa Earnhardt, over control of the team his late father built, it was expected that Earnhardt needed only the same equipment as champion teammates Jeff Gordon and Jimmie Johnson to make him a contender for championships.

Even Earnhardt himself said at the time, “There’s no excuses now.’’

But Earnhardt’s first three seasons at Hendrick failed to produce the desired results. He went through a pair of crew chiefs (including his cousin, Tony Eury Jr.), recorded just one victory in his first 108 starts, and qualified for just one Chase for the Championship.

“I was disappointed with how we ran,’’ Earnhardt said. “I wasn’t concerned that I was not going to get a new deal. If I didn’t get a new deal, then it was time to move on down the road.

“I had to keep an open mind whatever was going to happen. But I was happy he wanted to keep me around.’’

Special kind of pressure While Hendrick may have parted ways with any other driver after such a stretch, he was determined to see it through with Earnhardt.

Despite a winless streak that has now reached 120 races, Earnhardt remains one of the sport’s biggest marquee names and marketable figures, one who was voted Most Popular Driver for the eighth consecutive year last season.

“Dale wanted to be with us, and a tremendous amount of pressure came with being a teammate of Jimmie Johnson and Jeff Gordon,’’ Hendrick said. “And then you try to get the chemistry right and then you go through a slump and then you go through a confidence problem and then you go through all that.

“But I do not want to give up on him.’’

While he could take comfort in Hendrick’s words, Earnhardt’s struggles gave rise to a healthy dose of skepticism in racing circles about his abilities. Some wondered whether he was simply peddling on his family’s name. Or whether he was merely - gasp - overrated.

“I’ve got a lot left that I want to accomplish,’’ said Earnhardt, who this season was paired with Gordon’s former crew chief, Steve Letarte, and earned his second Chase appearance in four seasons at Hendrick, climbing five spots to fifth in the points after his third-place finish in last Monday’s Geico 400.

“I don’t know what I can accomplish these next five years to change the perception people have of me, because I’ve been doing it for a while, I guess,’’ he said. “Everybody’s got a different opinion. Some people have a high opinion of your abilities and other people don’t, but I think I’ve had a pretty solid career up to this point.’’

“That guy lives under pressure every day he gets up,’’ Hendrick said. “Some guys don’t have to live up to the expectations of what all his fans want him to do. Jimmie doesn’t feel that. Jeff doesn’t feel that.’’

Gordon agreed.

“When you look at the circumstances and what kind of pressures are on him, and expectations, it must be a tremendous burden,’’ Gordon said. “Obviously there are great benefits that come along with it as well, but the burden has got to be very tough.

“I don’t envy him at all, because it’s got to be a tough position to be in, and that’s why I applaud him for coming to Hendrick and saying, ‘This is the best team and this is where I want to be,’ knowing the success of the 24 and the 48.’’

An A in chemistry After watching Earnhardt struggle his first three seasons, Hendrick attempted to get him back on track this year by pairing him with Letarte, a native of Portland, Maine. Letarte’s task was as daunting as that of manager of the Red Sox - and subject to as much criticism.

“I’ve been labeled the cheerleader and motivator of the group, but Dale’s a big part of that as well,’’ said Letarte, who presided over a season in which Earnhardt qualified for the Chase after recording four top fives, including runner-up finishes at Kansas and Martinsville, and 10 top 10s. “The two of us have an interesting dynamic on the radio. There are times where he’s the guy setting the emotional tempo of the race and there’s times where I am.

“We have found a good balance there.’’

“I felt like the chemistry with Dale Earnhardt and Steve Letarte would be great,’’ Hendrick said. “So I’m extremely happy the way the thing has worked out.’’

Concerned about answering questions about his status at Hendrick in a negotiation year, Earnhardt wanted to take the proactive route. He wanted to avoid the public scrutiny Carl Edwards went through this year in deciding to stay at Roush Fenway Racing.

So Earnhardt phoned Hendrick to take his temperature.

“He called and said, ‘If you don’t want to go any further with me, I understand,’ ’’ Hendrick said. “And I said, ‘Hey, man, we’re done, we’re good. I want you here.’ And he said, ‘Well, good, because I want to be here.’ ’’

They reached a handshake agreement that seemed as easily negotiated as the first contract Earnhardt ever signed with Hendrick. That was when he was 15 years old and spent a week barnstorming with Kenny Schrader, who drove for Hendrick in late model cars, sprint cars, and ARCA cars.

Hendrick arrived at Heartland Park in Topeka, Kansas, to drive one of his own ARCA cars and met with the teen-aged Earnhardt in Schrader’s motorcoach while his father and Schrader were out practicing.

“He asked me what I wanted to do, and I told him I wanted to be a racecar driver,’’ Earnhardt said. “I told him what I had been doing and how I was going to make it to NASCAR one day.’’

Hendrick offered to help.

“So he wrote a contract on a napkin and asked me if I’d sign it,’’ said Earnhardt. “I don’t know what he did with it, but I know he wishes like hell he had it today. I wish he could find it.

“But I think it was more of a dig at my Dad, so he could go over and say that he had me signed up, locked up for life, that if I ever became a racecar driver, Daddy wouldn’t be able to reap the benefits from it.’’

Filling voids That napkin-and-handshake deal would lay the foundation of a friendship between Earnhardt and Hendrick that would be cemented under tragic circumstances, as each experienced the loss of a loved one.

“He’s been a guy I’ve been able to learn a lot from, and he’s filled some voids for me,’’ Earnhardt said. “He’s helped me grow and improve as a person, so I was appreciative of the opportunity. I knew he was a great person when I first met him.’’

Hendrick became a father figure to Earnhardt when Dale Earnhardt Sr. was killed on the last lap of the 2001 Daytona 500, while Earnhardt became something like a son to Hendrick when his own 24-year-old son, Ricky, died in a plane crash in October 2009 that also claimed Hendrick’s brother, John, and his 22-year-old twin nieces.

“I feel like me wanting to see him do well and kind of the void I’ve had losing my son and him losing his Dad, there’s some natural tendency for him to come to me with things in his life that he would’ve gone to his Dad,’’ Hendrick said.

“And for me to look at him like a son I want to see do well, I think that’s where it comes from, me saying, ‘I’m not going to give up.’ I’m going to keep digging and until we get it where we needs to be.

“I have developed a tremendous relationship, a friendship. And this is professional sports - you’re not supposed to let friendships and all that get in the way.

“But, to me, here’s a guy with talent. He’s a guy who took a chance in coming with us, he’s a guy who put his faith in me, and I’ll be damned if I don’t get him to where he needs to be.

“At the end of the day, I do not want to fail with him.’’

Michael Vega can be reached at vega@globe.com.