(Reuters) - U.S. stock index futures struggled for direction on Tuesday ahead of a crucial consumer price inflation report later in the week that could firm up bets on the size of the interest rate cut by the Federal Reserve on Sept. 18.

Apple's shares were down more than 1% in premarket trading as Huawei's tri-fold smartphone upstaged Apple's launch of its new series of iPhones and other products.

The iPhonemaker also lost its fight against an order by EU competition regulators to pay 13 billion euros ($14.34 billion) in back taxes to Ireland as part of an EU crackdown against sweetheart deals between EU countries and multinationals.

Most other megacap and growth stocks were also trading lower.

Wall Street's main indexes recorded gains of more than 1% on Monday as investors looked for bargains following a week of steep losses triggered by worries over the health of the U.S. economy amid elevated interest rates.

This week's focus continues to be on the August inflation reading on Wednesday that is likely to show a slight moderation in the headline number to 2.6% on a year-on-year basis, while it is expected to remain unchanged at 0.2% on month.

The producer prices report will be released on Thursday.

Money markets see a 73% chance of the U.S. central bank cutting interest rates by 25 basis points and expect the Fed to ease monetary policy by a total of 100 bps by the end of 2024, according to CME's FedWatch Tool.

"The Fed is walking a tightrope. A bigger rate cut could boost demand, but it also risks stoking inflation, especially if wages continue to rise despite the lower number of job openings," said Luca Santos, currency analyst at ACY Securities.

Later in the day, Philadelphia will be center stage when Kamala Harris and Donald Trump meet in a highly anticipated televised debate that could weigh heavily on the November election. The two, who have never met in person, will square off at 9 p.m. ET (0100 GMT) for a 90-minute debate hosted by ABC News.

At 04:44 a.m., Dow E-minis were up 6 points, or 0.01%, Nasdaq 100 E-minis were down 42.5 points, or 0.23%, and S&P 500 E-minis were down 1.5 points, or 0.03%.

Among other movers, Oracle jumped 8.6% after beating estimates for quarterly results and forecast second-quarter revenue growth above expectations, boosted by growing demand for its cloud offerings.

Hewlett Packard Enterprise dropped 6% after the AI server maker announced a $1.35 billion mandatory convertible preferred stock offering to fund its acquisition of Juniper Networks.

($1 = 0.9065 euros)

(Reporting by Shubham Batra in Bengaluru)