They crisscross the globe, dominating on almost every continent, one whacking a small, white ball better than anyone in the world, the other a fuzzy green one.
Tiger Woods and Roger Federer are making history in their respective sports, owning golf and tennis the way very few ever have. Over the weekend, they wrote new chapters in their march toward sports history.
No 1 in golf, Woods won his seventh straight PGA Tour event on Sunday in San Diego, a record eclipsed only by Byron Nelson back in the 1940s when the competition wasn't as tough.
No 1 in tennis, Federer won the Australian Open a half a world away, marking his 10th grand slam victory and furthering his quest to become the best tennis player ever.
Their excellence has united them over the years. They have become friends, and neither lets his own accomplishment go unnoticed by the other.
"He'll text me and say he won one there," Woods said in an interview Sunday on ESPN. "Now, I've got to text him and say we're all even."
It's a friendly rivalry between two men who never have to play each other -- the 31-year-old golf star and a 25-year-old counterpart on the tennis circuit. They are athletes who dominate in individual, sometimes lonely, sportsmen who recognize the commitment and sacrifice that must be made, even if the games they play may seem foreign to the other.
Last year, Woods was in Federer's box to watch his US Open victory. A few months later, Federer walked the course with Woods at a golf tournament in China.
Though many wonder how the joys of fatherhood -- his wife, Elin, is due with their first child next summer -- might affect him, Woods conceded his charge toward the top of golf's record book might be a more realistic quest than Federer's.
"The only thing going for me, is I've got longevity in my corner," Woods said, acknowledging the reality that golfers can play on a top level into their 40s, while tennis players fade out much earlier.
Not so long ago, Nelson's record of 11 victories seemed untouchable. Nelson racked up those wins under very different circumstances, before golf reached the heights it's at today and before seemingly every player had a swing guru and a personal trainer.
Though Nelson's record suddenly appears reachable, Woods remains focused on another number: 18. That's the number of majors Jack Nicklaus won. Woods entered 2007 with 12, and even if he misses the British Open to be on hand for his child's birth, he'll still be favored to win the other three this year.
But as much as Nicklaus, maybe Woods really should be keeping his eye on Federer, who's two majors short in tennis of where Tiger stands in golf.
As in golf, excellence in tennis can be judged either by dominance in the majors or by week-in, week-out success. Either way, Federer passes the test.
During the recently completed two weeks in Melbourne, he became the first man since Bjorn Borg in 1980 to go through a major without losing a set. Federer tied a 73-year-old record by making his seventh consecutive final in majors. He needs only four more Grand Slam wins to match the record held by Pete Sampras. "Breaking records and doing something that hasn't been done for a long time, it's really nice," Federer said.
Meanwhile, he already has enough points in the tennis standings to ensure he will break Jimmy Connors' record of 160 straight weeks atop the men's rankings by the end of next month. The only hole in his resume has been his inability to win the French Open, played on tricky clay courts in Paris each May. "I think it's going to be a very interesting French Open for me ... hopefully win the title," he said. "That will be a dream come true. That's the only way I can make this season a better one than last year. Otherwise it won't be possible."
But as the recently completed weekend proved, with these athletes, almost anything seems possible.