No. Though spiders are all strong for their size, the black widow is small compared to most members of, say, the tarantula family. A tarantula could overpower the black widow easily. There are many other spiders out there a good deal larger than the black widow, and they could best it in "combat" should the occasion arrise.
The strongest spider is the Goliath Birdeating Tarantula. It can over-power a fully grown parrot.