Woods came away with better statistics and the win.
The super sophomore caught 12 passes for 119 yards and two touchdowns as USC pulled away for the 31-17 victory.
Floyd managed just 28 yards on four receptions.
Sophomore cornerback Nickell Robey was matched up on the record-setting senior and frustrated him throughout.
"He did a great job of pretty much containing him all night," graduate assistant Sammy Knight said of Robey.
Floyd caught 11 passes for 86 yards and a touchdown last season at the Coliseum.
The undersized Robey spoke all week of his excitement to defend Floyd, regarded as a likely first-round draft pick.
"I came out there with a mindset I got to play my best game," Robey said. "Primetime weekend for me. I had a chance to showcase my talent to the world and I did that tonight.
Not So Special
Under special teams coordinator John Baxter, USC has always been able to rely on rock-solid performances there. Against Notre Dame, it nearly cost them.
Freshman running back George Atkinson returned a kickoff 96 yards for a touchdown, thanks in large part to a crushing block on USC running back George Farmer.
Kicker Andre Heidari also had his ankle stepped on during the play, later causing him to miss a 32-yard field goal.
"Bottom line is Andre is a tough kid," Baxter said. "And that kick that he missed, he would have never missed that like that. You know something's got to be wrong when that's the case."
Trainers had taped the ankle too tight, Heidari said. He was later able to kick an extra point and expects to be able to play next week against Stanford.
Armstead, Scout's top-rated player in the Class of 2012, was on an official visit to Notre Dame after decommitting from the Trojans last week.
Sophomore running back Dillon Baxter did not travel with the team, but school officials declined to say why.
USC head coach Lane Kiffin said he would likely update Baxter's status during his teleconference Sunday evening.