Within the space of a year they improved from seven victories before he joined the club, to 18.
In 28 matches during the 2001 campaign, Donovan scored 12 goals, including the equaliser in the MLS Championship Final.
With his potential then being realised at club level, albeit the MLS rather than the Bundesliga, Donovan was given a bigger role at the international level by US manager Bruce Arena.
Arena used his budding star in eight matches last year, including four World Cup qualifiers.
"I think I'm going to be in the squad," Donovan said with an eye on the World Cup.
"Right now I'm just fighting for a starting position, and that's difficult."
Barring injury, it is all but certain that Donovan will be heading to the World Cup as he has appeared in all 10 of America's matches in 2002, scoring four goals.
If his present form continues, he very well may win his fight to be in the starting 11 when the US faces Portugal on 5 June in their opening match.
Less clear is what will happen to Landon Donovan once World Cup 2002 has been completed.
"My agent has met with them (Bayer Leverkusen), and I think they want me back sooner rather than later; probably after the World Cup," Donovan revealed.