Williams received a four-week suspension for his 25th-minute shoulder charge on Watson which struck his head during the second Test, a pivotal moment in a game that ended with the Lions levelling the series with a 24-21 win in Wellington.
Watson admitted he had seen Williams closing in on him as he carried into contact.
“I remember everything, obviously it was a big tackle and I had to go off for the HIA but felt fine. Came back on and felt fine and have done all the protocols stuff so everything has gone to plan.
“I had to brace myself for it I guess, but it’s part and parcel of the game, so it is what it is.
“He messaged me on Twitter to say there was no intention and I don’t doubt that. I don’t think he’s a malicious player so I don’t think he intentionally led with his shoulder to hurt me or anything like that. It’s just unfortunate I guess.”
Asked if that hit had been the biggest he had received, the 23-year-old did not have to go too far back into the memory bank for his answer, referring to an England training session accident last November.
“It’s up there,” Watson said of the Williams hit. “Marland Yarde broke my jaw in the autumn actually, running into his head, so that was probably the only one worse.”
Watson is appreciative of his Lions experience and is also aware of the chance to make some history in the famous red jersey if a series win is completed tomorrow.
“It’s pretty hard to put into words.
“For me it has been all about learning as much as possible and trying to be a sponge off all the guys around me, guys like Alun Wyn Jones, Johnny Sexton, even Owen (Farrell, his England team-mate) in a different environment is a different animal.
“For me, it has been about being a sponge and trying to learn as much as possible.
“It’s one shot, isn’t it, you only get one opportunity. You only get one chance to really go out there and do it. For me, it is about maximising the opportunity and impacting the game wherever I can,” he added.