US STOCKS-Futures point to flat open on weak earnings

* Indexes on track to break three-week streak of losses

* UPS shares fall after outlook, Starbucks (Swiss: SBUX.SW - news) up on results

* Oil falls, on track for another negative week

* Futures down: Dow 7 pts, S&P 3 pts, Nasdaq 3 pts (Updates with UPS outlook)

By Ryan Vlastelica

NEW YORK, Jan 23 (Reuters) - U.S. stock index futures pointed to a flat open on Wall Street Friday, as early gains following a sharp rally in the previous session were offset by some weak corporate results.

Wall Street jumped more than 1 percent on Thursday, an advance that returned the S&P 500 and Nasdaq to positive territory for the year and set the key indexes on track to break a three-week streak of declines. The move came after the European Central Bank detailed a bigger-than-expected bond-buying program designed to boost the region's sagging economy and fight deflation.

With the ECB stimulus details known, U.S. corporate earnings will likely be the primary driver of trading over the next few weeks, and a number of bellwether names have disappointed, with revenue being a particular area of concern.

United Parcel Service Inc (Xetra: UPAB.DE - news) gave a fourth-quarter earnings outlook that was below expectations, citing a disappointing performance in U.S. domestic ground shipments. Shares (Frankfurt: DI6.F - news) slumped 8.4 percent to $104.65 in premarket trading.

Dow component McDonald's Corp reported a drop in fourth-quarter revenue and said it expected its January comparable sales to be negative. However, shares rose slightly before the bell.

General Electric Co shares dipped in premarket after the Dow component reported that sales fell in its oil and gas unit, though overall earnings rose.

With 15 percent of S&P 500 companies having reported, 73.7 percent have topped earnings expectations while 53.9 percent have beaten on revenue, according to Thomson Reuters data. That compares with the long-term average of 63 percent for earnings and 61 percent for revenue.

Starbucks Corp rose 4.8 percent to $86.70 in premarket trading a day after the coffee chain reported same-store sales growth that was better than expected in its Americas region.

Crude oil prices will continue to be in focus, with additional uncertainty coming in the wake of the death of Saudi Arabia's King Abdullah. While the country's oil policies are expected to be unchanged, the commodity has been extremely volatile of late, with its value dropping by more than half over the past six months. Oil fell 1.1 percent on Friday, reversing earlier gains, and was on track for its 15th negative week out of the past 17.

While the drop in crude prices is seen pressuring the profits of energy shares this quarter, it could lift stocks in the transportation, retail and industrial sectors.

For the week, the Dow is up 1.7 percent, the S&P 500 is up 2.2 percent and the Nasdaq is up 2.5 percent. All three are coming off three straight negative weeks.

Thursday's rally took the S&P 500 above its 50-day moving average, a metric of near-term momentum that the benchmark index hasn't closed above since Jan. 8.

Futures snapshot at 9:00 a.m.:

* S&P 500 e-minis were down 3 points, or 0.15 percent, with 189,661 contracts changing hands.

* Nasdaq 100 e-minis were down 3 points, or 0.07 percent, in volume of 28,186 contracts.

* Dow e-minis were down 7 points, or 0.04 percent, with 26,972 contracts changing hands.

(Editing by Bernadette Baum)