FTSE gains as Citi results buoy banks

* FTSE up 1.7 pct, first weekly gain in nine weeks

* Citigroup results help banks' rally

* Miners sag, Tesco succumbs to retail sell-off

By Amanda Cooper

LONDON, July 18 (Reuters) - British blue-chip stocks rose on Friday as banks rebounded after better-than-expected results from U.S. bank Citigroup (C.N: Quote, Profile, Research) in the choppiest session in nearly six months, while a fall in miners curbed gains.

The FTSE 100 .FTSE ended up 90.1 points, or 1.7 percent, at 5,376.4 points, bringing the rise for the week to 1.9 percent, making this the first weekly increase in nine weeks and the end of the longest losing stretch since late May 2002.

In this latest slide, the index has lost over 15 percent.

The FTSE swung between a loss of 1.3 percent and a gain of 1.4 percent in its most volatile day of trade since Feb. 2.