Ninjutsu
Without competition Kakuzu has mastery here. Having all but the water element manga wise, Kakuzu has the elemental advantage for even if Sakura pulled a Katon, Kakuzu can enhance fire with wind to trump it.
However, the key here is Doton: Domu (Earth Spear). This move gives Kakuzu Diamond hard skin. Diamond is the hardest known substance on the earth, and is basically unscratchible based on Moes hardness scale. As such, a physical blow isn't going to damage Kakuzu because it isn't even a cutting technique. Diamond itself is formed under EXTREME pressure which is why it is mined.
So if Sakura can even land a blow, Doton: Domu trumps it to mAke it useless.
Taijutsu
Kakuzu wins once again. First and foremost, Sakura is a medical ninja meaning her PRIMARY focus is on healing. However, her secondary role would be to actually fight. As we saw in her fighting with Kakashi, she is more of a heavy hitter as opposed to a speed demon. She could jot land a single strike on Kakashi.
Comparatively, Kakuzu thrashed Kakashi when it came to Taijutsu battle. Combining his thread body to extend his reach and grapple joints to prevent movement, Kakuzu overwhelmed Kakashi who is a sharingan user (meaning Kakadhi could read his moves, but still could not dodge them).
Genjutsu
Neither use much genjutsu, but Sakura is noted to be adept in detecting it
Strength
Sakura has superior strength, but Kakuzu also has a strike powerful enough to break steel doors. Even if she's a good medic that's a painful shot.
Intelligence
Once more Kakuzu stands on top. He has grown up being a shinobi and has lived for 92 years. His experience and tactics far surpass Sakura. Considering he grew up in the same war stare era as Hashirama...his combat intelligence is only more refined. And even more so since even when growing up and finally being consent to assassinate Hashirama...he did not have his Earth Grudge Fear. So with only one or two elements like any average Jounin he fought and survived Hashirama.
Hand seals
Neither particularly them.
Speed
Kakuzu has shown more impressive speed feats.
1. Coming out of nowhere on Shikamaru
2. Speed blitzing Asuma with imbalances weight between Hidan's head, and a briefcase.
3. Going from face down, he speed blitzed Kakashi who sprinted towards Hidan.
4. Managed to have the speed to send his tendrils underground and catch Kakadhi, Ino, and Choji before Kakadhi registered it.
In battle, Kakuzu would most likely win. He would be able to fight against Sakura alone with Doton Domu as the masks fended off Katsuyu. Between Fuuton Asugai, Katon Zukkaku, and Raiton Gian, they would be able to hold her back. If she were to use acid, Asugai (air pressure damage) would be capable of blowing it back as it is a liquidous substance and from what Katsuyu showed, simply spreads out similar to Youton (lava release) as opposed to a projectile. A combination of three elements should theoretically suffice to counter it alone.
Additionally, the masks are extremely mobile (capable of facing Kakashi), and to some degree losses the ability to fly (the wind mask for a fact).
In Taijutsu hand to hand, I do not see Sakura wining. Considering his experience, Kakuzu would likely be able to dominate here. Sakura has been known to use traps and poison; however, she hasn't shown a consistent trap style, and I highly doubt Kakuzu loses to random poison bombs with his experience. Kakuzu has even been around a Tailed Beast Rampaging Ginkaku so I'd say to some degree he'd be familiar with acidic styled offensives (considering the Bijuu transformation skin
sis supposed to burn opponents).
Kakuzu wins in my opinion. Hw has too much experience and skill in hand to hand. Has the numerical and elemental strength to keep Katsuyu at bay, and his Doton: Domu is capable of countering Sakura's physical punches.