During Friday night’s NL East clash between the Washington Nationals and Philadelphia Phillies, all eyes will be on the two teams’ respective aces: Stephen Strasburg and Cliff Lee. It’s early going, but both pitchers are having outstanding seasons; Strasburg is second in the major leagues in strikeout percentage, while Lee walks opposing batters at the majors’ second-lowest rate.

But while Strasburg is essentially doing what’s expected of a 25-year-old pitching phenom, Lee is 35 — and yet he’s never been outpitched by Strasburg in a season, at least not according to wins above replacement (either version).

In fact, sabermetrician Tom Tango runs a Lee vs. Strasburg poll almost every year. Lee was a 3-to-1 favorite to out-WAR Strasburg in the wunderkind’s rookie season of 2010 and again in 2012 (Strasburg was out most of 2011 after undergoing Tommy John surgery in 2010). But in 2013, it was assumed the much younger Strasburg would finally pass Lee if he came anywhere near the 159⅓ innings he’d tossed in 2012. Dan Szymborski’s ZiPS projection system estimated there was better than a 77 percent probability that Strasburg’s park-adjusted ERA would be better than Lee’s.

It wasn’t. Strasburg put up an ERA 20 percent better than average; Lee’s ERA was 24 percent better than average. Lee also came out ahead in Fielding Independent Pitching (FIP), while also pitching 39⅔ more innings than Strasburg. That’s why Lee crushed Strasburg by two to four WAR, depending on which system you look at.

The two pitchers have more than their share of similarities, despite throwing from different sides of the rubber. Strasburg is better at striking out batters; Lee has better control. But both have been among the most dominant pitchers in the game over the past couple of seasons. It’s just that Lee was born in 1978, and Strasburg 1988.

Such an age difference is amplified by how each arrived where they are now. Strasburg’s route was relatively direct, aside from an injury detour in 2010-11. He was one of the most hyped pitching prospects in baseball history and has largely lived up to that promise (literally, from Day 1 of his Major League Baseball career). Lee’s path was far more circuitous, which may explain why he manages to fly under the radar despite being baseball’s most valuable pitcher over the past seven seasons.

At any rate, Tango’s voters appear to have learned their lesson this year, picking Lee by a narrow margin. And sure enough, the ageless Lee has picked up right where he left off, leading Strasburg in ERA, FIP and, therefore, both flavors of WAR.

Eventually Lee will have to relinquish his lead, but who can say when?