David Letterman, Conan O'Brien David Letterman, Conan O'Brien

On their seventh day of head-to-head competition, David Letterman's Late Show squeaked past Conan O'Brien's Tonight Show, though by a slim margin — one half of a rating point. 

Still, Letterman's latest performance represents a 13 percent week-to-week gain, while Conan has dropped 42 percent since his Tonight Show debut.

The Tonight Show's numbers, in fact, have declined every night since O'Brien seized the reins on June 1. To be fair, on Tuesday night he was hampered by soft lead-in numbers courtesy of NBC's NHL coverage.

Letterman's guests for Tuesday were Julia Roberts (who told her host, "You are so much funnier than other people who talk at this time of the evening") and the Black Eyed Peas, while O'Brien welcomed Eddie Murphy, The Office's Angela Kinsey and Bonnie Raitt.

The last time Dave topped The Tonight Show was on consecutive nights in mid-October 2008, with guests John McCain and Tina Fey.

Elsewhere on Tuesday: 

•  ABC's coverage of the NBA Finals averaged 9.6 mil, while NBC's NHL Stanley Cup broadcast scored 5.45 mil. Both sporting events got beat by CBS repeats of NCIS and The Mentalist (the non-jock in me must point out).

• Fox's Mental — featuring a dialogue-free guest-star turn by David Carradine — delivered 4.83 million total viewers, dipping 210K.