* Euro weakens before crucial ECB meeting * Higher-risk currencies firmer; dollar and yen off multi-month highs * Graphic: World FX rates tmsnrt.rs/2RBWI5E LONDON, July 22 (Reuters) - The euro traded just off 3-1/2 month lows versus the dollar on Thursday before a potentially momentous meeting of the ECB, while growth-focused currencies such as the Australian dollar gained as a global risk sell-off abated further. The U.S. dollar index and the yen which rose earlier this week to the highest since early-April and end-May respectively, retreated as strong earnings lifted stock markets and bond yields, and induced investors to trickle out of the safe-haven assets they had piled into. They also bought back into cryptocurrencies, with bitcoin rising further above the $30,000 mark, especially after Tesla CEO Elon Musk said the company would “most likely” resume accepting bitcoin for payment. No new measures are anticipated from the European Central Bank but following on from the inflation target tweak, odds have risen on policymakers promising to retain support for longer and even to add more bond-buying. The euro traded at $1.1790 by 0800 GMT, just off the early April lows of $1.1752 touched on Wednesday. The ECB’s dovish pivot at a time when many peers are mulling exiting pandemic-era stimulus is expected to keep the single currency under pressure. “A lot of what happens today with the ECB hinges on just how much of an inflation-averaging central bank Lagarde and the press conference portray them as,” said Stephen Gallo, European head of FX strategy at BMO Capital Markets. “The more they look willing to tolerate a significantly higher rate of inflation, the more negative it will be for the euro, bullish for commodity and emerging market currencies versus the euro.” He added, however, that much hinged on how much consensus there was within the governing council to extend bond-buying once pandemic-time stimulus expires in March. The dollar index =USD, which measures the currency against six major peers, slipped to 92.75 after pulling back from a 3-1/2 month high of 93.194 touched on Wednesday. The yen, another safe-haven, was at 130 per euro , from an almost four-month top of 128.610 hit this week, and was flat versus the dollar at 110.3 yen. The Australian dollar changed hands at $0.73675, from an eight-month low of $0.72895 the previous day, despite half the Australian population being under COVID lockdowns. It also firmed against the yen which was at 81.07 , from a 5-1/2 month peak of 79.85. The gains in higher-risk assets come too after robust company earnings lifted Wall Street and European bourses, allowing investors to look past concerns that the Delta Covid-19 variant would dampen the economic recovery. “The consensus is that (the Delta strain) does not pose an immediate risk to the recovery,” delaying reopening by three months at the most as countries ramp up vaccination drives”, National Australia Bank analyst Tapas Strickland told clients. Sterling firmed to $1.374, recovering from 5-1/2 month troughs while in cryptocurrencies, bitcoin held Wednesday’s 7.9% jump - the biggest since mid-June - to trade just north of $32,000. Reporting by Sujata Rao; additional reporting by Kevin Buckland in Tokyo;Editing by Elaine Hardcastle Our Standards: The Thomson Reuters Trust Principles.