Team Sky star Chris Froome's attempt to win a third straight grand tour got off to a nightmare start at the Giro d'Italia on Friday.

With so much talk about his adverse test for asthma drug salbutamol at last year's Vuelta and whether he should even be here, the start of the race was meant to bring some respite.

The four-time Tour de France champion's bad day at the office began when he crashed heavily on his right side during a reconnaissance ride of the 9.7-kilometre course, a twisting and undulating route around Jerusalem's city centre.

His team said it was just a case of cuts and bruises but that looked like an understatement four hours later when he went through the intermediate split way down on the early leader Rohan Dennis.

That impression was rammed home less than four minutes later when the last man on the course, defending champion Tom Dumoulin, went through the finish line in a blistering time of 12 minutes two seconds - two seconds quicker than Dennis and a massive 37 seconds better than Froome, whose time was good enough only for 21st on the day.

The third fastest man on a warm and sticky day was Belgium's Victor Campenaerts, only a fraction of a second slower than Dennis, with Portugal's Jose Goncalves fourth, 12 seconds back.

Ryan Mullen, riding for the Trek - Segafredo team, was the best of the Irish trio in this year's opening stage.

The time-trial specialist had been targeting a strong finish on the first day of this year's race but finished 57 seconds off the lead in 62nd place.

Further down the field were Irish duo Nicolas Roche and Sam Bennett - 74 and 79 seconds slower than Dumoulin, respectively.

Ireland's Nicolas Roche

Australia's Dennis, a specialist over short distances, had sat in the so-called hot seat as the man to beat for over two hours but none was hotter than Dutchman Dumoulin.

The world time-trial champion now knows he should be able to put serious amounts of time into all his rivals for the general classification in the Giro's second time-trial, a longer, flatter effort at the start of the third week on May 22.

Froome, however, will be desperate to wrest back control of this race by then and he will get chances to do so, with five of the Giro's eight mountain-top finishes coming before that 16th stage, but he will need to show much better form than he displayed here.

The fact he lost nearly all of his deficit to Dumoulin in the more technical first half of the course suggests he was struggling to accelerate out of corners and he also appeared to be cornering very conservatively - both understandable results of a painful tumble.

Losing to Dumoulin and Dennis on this course is no major embarrassment but the fact he is also behind Italy's Domenico Pozzovivo and Frenchman Thibaut Pinot, two challengers for victory in Rome in three weeks' time and neither known for their time-trialling, will smart.

And the fact that a trio of climbers - New Zealand's George Bennett, Italian Fabio Aru and Colombian Miguel Angel Lopez - who also crashed whilst checking the course, are only just behind would not have been part of the plan.

For many of the riders, this time-trial was more of a warm-up for Saturday's 167-kilometres ride up the Mediterranean coast from Haifa to Tel Aviv, where a bunch sprint is practically guaranteed to erupt by the seaside.