Some interesting numbers from the 1/4/99 Raw and Nitro.
Yes, when Tony Schiavone told people that Mankind would be winning the title, Raw gained roughly 375,000 homes and a total of 600,000 viewers. However a little known fact is, The Rock vs. Mankind match actually lost viewers, while the Finger Poke of Doom gained viewers.
RAW (2 hour show)
QH #5: D'Lo vs. Edge [1st Schiavone Foley comment] (5.2)
QH #6: Kane vs. Patterson/Brisco [2nd Schiavone Foley comment] (5.7)
QH #7: Road Dogg vs. Al Snow (5.7)
QH #8: Rock vs. Mankind (6.2)
QH #9: Rock vs. Mankind (5.9)
Overrun: Rock vs. Mankind (5.1)
NITRO (3 hour show)
QH #8: Hogan interview [1st Schiavone Foley comment] (5.1)
QH #9: Steiner vs. Konnan [2nd Schiavone Foley comment] (5.1)
QH #10: Wrath vs. Bigelow (4.7)
QH #11: DDP vs. Brian Adams (4.1)
QH #12: Finger Poke of Doom (4.6)
Overrun: Finger Poke of Doom (6.5)
"While the big switch of audiences to see Foley win the title is much remembered, what is forgotten is that after Foley won the title, a Goldberg run-in on Nitro and Austin run-in on Raw were going on at the same time for the overrun. Goldberg saw Nitro bring its audience back, going from a 4.6 to a 6.5, taking many of those viewers back from Raw which went from a 5.9 to a 5.1. The growth of the final segment of Nitro, was an incredible 2.1 million viewers, among the biggest growth periods in history. Between the two shows on that night during the overrun, there were 8,642,000 homes and 13,827,000 different viewers watching wrestling. And keep in mind two other factors. There were only 74.5 million homes with cable on that night, compared with more than 99 million today. And going head-to-head with wrestling that night was the Fiesta Bowl game that determined college football’s national championship, which had nearly 30 million viewers." - Wrestling Observer Newsletter [July 31, 2012]