Cubs fans wept in Chicago on Wednesday night. Boston Red Sox fans will never overcome Thursday night's collapse. For these teams and their loyal fans, losing was not the most painful part; it was the way they lost that hurt so much.

Both teams came agonizingly close to turning back years of frustration. Each had moments where they could sense victory, but in inexplicable fashion they found a way to lose.

Again.

Winston Cup points leader Matt Kenseth can learn from what transpired in the baseball world this week. The lesson? Letting a championship opportunity slip through your clutches is hard to accept. It's real hard.

Kenseth heads into Sunday's Subway 500 in Martinsville with a 267-point lead over Kevin Harvick. However only three weeks ago, Kenseth left Dover with a 436-point advantage. Now with five races remaining in 2003 he realizes the Winston Cup Championship is his to lose and he's far from comfortable.

"The bigger your lead is with less races to go you definitely think about it more, but I still think it's at a point where we could still mess it up," said Kenseth, who averages a 20th place finish in seven Martinsville starts. "We have to make mistakes and have mechanical difficulties and have wrecks. We'd have to have things happen to be able to lose that many points, but that's not to say those things can't happen."

There's been abundant evidence of that recently. Kenseth had engine failure in Talladega and crashed in Kansas. This enabled Harvick to chop 177 points from Kenseth's lead.

Kenseth finally stemmed the tide last week in Charlotte, finishing two positions ahead of Harvick. But it was during that event that the championship pressure became evident when he voiced his displeasure with Harvick during the race.

"He's just playing mind games and trying to get as close as he can to me to get the air off of me without hitting me," Kenseth explained after finishing eighth in the UAW-GM 500. "He was hoping I'd mess up or make a mistake or crash. I don't necessarily blame him for doing it, but he cost us both a lot of time. Both of us would have finished up farther if he hadn't done that because we could have gotten single file and made better time than messing around side by side for 20 laps."

Beginning with his Brickyard 400 win on Aug. 3, Harvick has climbed steadily from seventh in the standings. Now his spirited charge is drawing comparisons to Alan Kulwicki's 1992 championship effort.

That year, Kulwicki trailed Bill Elliott by 278 points with six races remaining. Elliott blew an engine in Martinsville and broke a sway bar two weeks later in Charlotte. He finished 30th in both events and effectively opened the door for Kulwicki and a number of others. With two races remaining in '92 Elliott turned the point lead over to Davey Allison after suffering more engine woes in Phoenix.

Entering the final event in Atlanta, five drivers were within striking distance of the title. Allison led Kulwicki by 30 points, Elliott by 40, Harry Gant by 97, Kyle Petty by 98 and Mark Martin by 113.

Allison needed to finish sixth or better to clinch, but on lap 253 of 328 he crashed. As the championship slipped through his fingers Kulwicki was there to catch it. Elliott won the race but Kulwicki finished second and led the most laps, enabling him to win the championship by just 10 points.

There are similarities between 1992 and now. There are differences too; there were six races remaining then and only five now. Harvick is fighting the dwindling schedule and there is little he can do to control his own destiny. Still, Kenseth isn't taking anything for granted.

"Obviously, the farther into the season it gets, the better I feel about it. However, we still have enough racing left where somebody could overcome this lead," added Kenseth. "I don't get overly confident or count my chickens before they hatch. I just think when we get to the end of the year, I'll sit back and enjoy it if we are lucky enough to get this thing pulled off."

Some would argue that good luck is a product of hard work. The Cubs and Red Sox may not be included in that group right now, but Kenseth is.

"We just have to still run hard, try to win races and just see how it ends up," asserts Kenseth, who is hoping to become just the fourth Ford driver to win the championship during the modern era. "I just look at every week and honestly wish (the lead) was a little bit bigger. I'd feel more comfortable (laughing). I'm happy with where we're at and I'm definitely a lot more comfortable than if we had a 100-point lead because we are a couple of races ahead, so that gives us a little more confidence."

Kenseth needs to average a 10th-place finish over the next five races to clinch the championship. Considering he leads the series with 23 top-10 finishes he seems to be in a good position. But he needs to stay focused and maintain his methodical approach, otherwise he could be saying the same old thing as the folks in Chicago and Boston -- 'wait until next year.'

Mike Massaro covers NASCAR for ESPN and ESPN.com.