UPDATE 1-F5 Networks 4th-qtr profit beats Street; shares up

* Q4 adj EPS $0.50 tops estimates by 9 cents

* Q1 earnings forecast beats estimates

* Shares rise 8 percent in trading after the bell

Oct 21 (Reuters) - Network-equipment maker F5 Networks Inc's (FFIV.O) quarterly profit beat market estimates on increased bookings and improved customer spending, sending its shares up 8 percent.

The company also gave a strong outlook for the first quarter.

Fourth-quarter net income increased to $28.4 million, or 36 cents per share, from $19.7 million, or 24 cents per share, a year earlier.

Revenue rose about 2 percent to $175.1 million.

Excluding items, earnings were 50 cents a share.

Analysts expected earnings of 41 cents a share, excluding exceptional items, on revenue of $163.9 million, according to Thomson Reuters I/B/E/S.

For the first quarter, the company -- whose rivals include Cisco Systems (CSCO.O) and Juniper Networks JNPR.O -- forecast earnings of 47 cents to 49 cents, excluding items. Analysts were expecting 43 cents a share.

Shares of the Seattle-based company, were up $2.87 at $44.40 in trading after the bell. They closed at $41.53 Wednesday on Nasdaq. They have gained about 84 percent this year. (Reporting by S. John Tilak in Bangalore; Editing by Saumyadeb Chakrabarty)