I disagree strongly, I believe she can beat Kakashi. Won't explain here, written too many paragraphs about it. But to summarize..
Tsunade has better stats than Kakashi overall.
Kakashi's Kamui has never accurately worked on a shinobi. The only time it somewhat worked was with Deidara's arm and Tsunade can recover from that with Creation Rebirth in an instant.
Most of Kakashi's jutsus are recoverable by Tsunade's Creation Rebirth.
For example:
Raikiri - Yes, she can create missing organs and if the injury is less, well obviously she can recover.
Fireball - Superficial burns, she can recover.
Tsunade can simply take a Raikiri to the chest, and then punch Kakashi straight in the face, or paralyze him with her Body Pathway Derangement technique. Unlike Kabuto, Kakashi doesn't have the antidote or the necessary knowledge of medical ninjutsu to overcome this paralysis.
If all else fails, she can just summon Katsuyu.
Offensively - Giant and attack with Acid. Or divide it into million Katusyu's and all attack at the same time with Acid.
Defensively - heal and provide block (since there are so many)
With Creation Rebirth, regeneration is almost instant. She will survive and regenerate from a Raikiri to the heart. Yes, she can regenerate from a Kamui, even if the part (an arm) is gone. When you regenerate something you create it again. This is explicitly what the technique does.
When one's heart is pierced, you don't die immediately. Look at Asuma. (If he didnt get stabbed in the heart..well..my point still stands)