Rory McIlroy’s miserable run of form showed no sign of abating as he shot an opening-round 78 to finish six over par on the first day of the Memorial Tournament in Ohio.

The Northern Irishman missed the cut at the BMW PGA Championship last week, admitting he had been put off by poor weather at Wentworth.

This week’s tournament in Dublin offered McIlroy the chance to put that behind him with the US Open only a fortnight away, but he failed to fire once again.

Starting on the back nine, McIlroy had an ideal first hole with a birdie at the par-four 10th, but it was all downhill from there.

A double-bogey at the 12th heralded a woeful day, with a further three bogeys racked up before the turn.

There was no respite on the front nine as he hit a further three bogeys, interspersed with a birdie at the fifth, before squandering birdie chances at the final two holes.

England's Lee Westwood also endured a miserable opening round of 76.

The Englishman had appeared to be on the brink of victory last week at Wentworth only to squander a two-shot lead in the final round.

While not as disastrous as the round of his Ryder Cup team-mate, Westwood looked in the doldrums as he hit three bogeys and a double-bogey on his way to a four-over total.

In contrast, South Africa's Charl Schwartzel made up for hitting a bogey and a double-bogey with 10 birdies seeing him to a seven-under-par 65.

That was one shot ahead of Scott Piercy, who hit eight birdies – five of them consecutively on the front nine – only to drop shots at the 12th and 18th.

A further shot behind were Josh Teater and Russell Henley, who both shot 67s.

World number one Tiger Woods and Ireland's Shane Lowry were among the later starters.