You win some, you lose some. That's how shareholders of Alcatel-Lucent (NYSE:ALU) must feel right now.

On the heels of landing a major supplier contract for AT&T's (NYSE:T) Long-Term Evolution network plans, Alcatel reported a deeply disappointing fourth quarter that made investors forget all about the good news. Sales fell 17% year over year, assuming constant currency exchange rates, to $5.4 billion. Earnings fell from last year's normalized $0.10 per American Depositary Receipt to $0.03 per ADR -- but that includes $0.12 of positive accounting adjustments this time around. Without those one-time items, Alcatel shows a normalized loss of closer to $0.10 per share.

The stock tumbled by 12% on Thursday on a generally positive market day. Rivals like LM Ericsson (NASDAQ:ERIC), Motorola (NYSE:MOT), and Cisco Systems (NASDAQ:CSCO) all fared much better, so Mr. Market seems to believe that Alcatel's problems in the quarter were uniquely Alcatel's, and not some nebulous sector effect.

Alcatel's stock is still up a market-beating 60% over the last year, but down by a soul-crushing 78% in the past five. It's enough of a thrill ride to make Spider-Man reach for the antacids. I recount the recent history of Alcatel-Lucent to my kids every Halloween. (OK, I don't. That would just be cruel.)

It takes a daring investor indeed to jump aboard this bandwagon, and a two-star CAPS rating hardly inspires confidence, either. But the global market for next-generation wireless network equipment represents enough of an opportunity to outweigh weakness in other sectors, and the AT&T deal proves that Alcatel has what it takes to land those crucial contracts.

So I think that yesterday's drop could be a fine buy-in opportunity. AT&T and Verizon (NYSE:VZ) will need to increase their equipment orders as the 4G trains get rolling for real, and then there are entire continents of emerging economies that need some wireless love. It's way too early to dismiss Alcatel now, despite last quarter's disappointments.

That's my two cents. What do you think?

Fool contributor Anders Bylund holds no position in any of the companies discussed here. You can check out Anders' holdings and a concise bio if you like, and The Motley Fool is investors writing for investors.