Sussex 397 for 5 (Orr 206, Pujara 66) beat Somerset 196 (Currie 3-38, Coles 3-31) by 201 runs
The 21-year-old left-hander hit a brutal 206, off 161 balls, with 11 sixes and 18 fours, to help his side post 397 for five after losing the loss. Cheteshwar Pujara contributed 66 and Delray Rawlings 54 not out off just 23 deliveries.
Orr eclipsed the previous highest individual innings by a Sharks player, the 174 made by Pujara against Surrey at Hove just five days earlier, and earned a share of fifth place among the top scorers ever in List A cricket.
In reply, shellshocked Somerset were bowled out for 196 in 38.2 overs as they fell to a seventh defeat in as many group matches and their heaviest ever in List A cricket by a margin of runs. Only Andrew Umeed, with 56, offered much resistance.
Apart from a three-over opening burst from Jack Brooks, Somerset’s seamers lacked any semblance of control on a true pitch and Orr was in just the mood to capitalise.
His first fifty occupied 45 balls, the second 61, the third 24 and the fourth 29 as he mercilessly punished anything off line, launching the vast majority of his sixes over mid-wicket and long-on with impressive bat speed.
It was murderous display that required just one moment of luck. On 66, he edged Alfie Ogbourne through to wicketkeeper James Rew, who took a diving catch, only to see that a no-ball had been signalled.
Other than that, Orr, whose previous best List A score in only 11 games was 108, produced a display of clean hitting rarely matched at ground renowned for fast scoring.
From 61 for two, Danial Ibrahim having edged Brooks to Matt Renshaw at slip and Tom Clark been run out in a mix-up with Orr over a quick single, Sussex assumed total dominance.
Pujara characteristically picked up ones and twos in a stand of 140 for the third wicket. The Indian maestro also hit 5 fours and a six before being caught and bowled by Kasey Aldridge off a leading edge.
Fynn Hudson-Prentice supported Orr with a solid 36 in a partnership of 98. When he was caught at long to give slow left-armer Josh Thomas a maiden List A wicket, Rawlings strode out to inflict more heavy punishment.
Three sixes and 6 fours helped him to a 22-ball half-century, while at the other end Orr continued to plunder runs. When the opener was finally caught at long-off in the final over of the innings, spectators all around the ground stood to applaud.
It took just eight deliveries of the Somerset reply for the Sharks bowlers to show what was possible with line and length, Bradley Currie swinging a ball away from Rew and having him caught at second slip.
Lewis Goldsworthy, who had been given only seven overs despite being the pick of Somerset’s bowlers, dragged a ball from Currie onto his stumps and skipper Matt Renshaw edged a catch behind off Aristides Karvelas to leave the hosts 26 for three.
Having been forced by injuries and Hundred call-ups to sign Gloucestershire all-rounder George Scott on a two-match loan, Somerset were facing humiliation.
So it proved, as George Bartlett was caught at mid-off advancing down the pitch to Henry Crocombe, who then had Thomas caught at cover off a total mishit.
Umeed moved steadily to a maiden List A fifty off 47 balls. But he was caught at slip off the first over from slow left-armer James Coles and when Rawlins had Aldridge caught behind it was 114 for seven.
Scott, Brooks and Ogborne, who smacked Rawlins for a straight six, produced some belligerent tail-end blows to boost the meagre total. But for Somerset it was another disastrous day in a calamitous 50-over campaign.