If the strains of The Flower of Scotland were heard at Potters Leisure Resort in Hopton-on-Sea yesterday, it was hardly surprising, because the day belonged to the Scots, who dominated proceedings at the Fred Olsen Cruise Lines world indoor singles championship.

Of course, it was no surprise that serial title winners Paul Foster and Alex Marshall came through their opening matches, but a couple of unseeded Scots also caught the eye and upset England's applecart by casting two eminent seeded players in the unaccustomed role of first round losers.

First it was Colin Walker, a 37-year-old sawmill foreman, and Scottish PBA qualifier from Midlothian, who tore up the script by beating the number two seed, world number one Greg Harlow, from the City of Ely club, on a tie-break, 9-4 3-9 2-1.

That was the cue for Alloa's Steven Allan, a 26-year-old machine operator at a yeast factory, who received a special invitation to compete at Potters as a reward for winning the rival code's WIBC world title last April, to topple world number eight Simon Skelton, from Nottingham, 8-8 7-5.

Walker's win over Harlow was, he said, the highlight of his career, but he had to do it the hard way, after losing the initiative in the second set, and dropping the first end of the tie-break.

Holding his nerve, he drew close to the jack on the last two ends, and Harlow, who admitted that line and length were hard to find, was unable to save the situation.

Allan, who had to come through a four-match round robin to clinch a place in the main event, did so without dropping a set against opponents from the USA, Canada, Israel and Hong Kong, and was always on top of Skelton.

The Nottingham star did well to tie the first set, scoring two doubles to draw level at 8-8, and he finished well in the second set, scoring two singles and a double on the last three ends – though, by that stage, he was already 1-7 adrift.

'I always knew I had the game to hold my own at this level, but the atmosphere of the portable rink is different from anything else in the sport, and you can't be sure until you have been tested under these conditions,' said Allan, who wore a broad grin.

Both Walker and Allan were not sure what bowls to use on the carpet, and had borrowed the very same set of green bowls from their legendary fellow-Scot David Gourlay.

Although Alex 'Tattie' Marshall defeated Brighton's Scott Edwards, 9-8 8-6, he found the England PBA qualifier a tough nut to crack, and was the first to admit that he will have to improve his form against David Gourlay or Kelvin Kerkow, who meet today, if he is to make further progress.

Five times champion Marshall needed to produce three miraculous bowls to win the first set, and was facing a set lie when he delivered his last bowl of the second set, when, with a little help from Lady Luck, he glanced in off a short bowl to clinch the winner.

Admitting it was the first time he had come across his opponent, who plays for the Adur club in Southwick, Marshall observed: 'Anyone who comes through the UK PBA play-offs is bound to be a good player, so I was prepared for a hard tussle.'

Last night, Foster crowned a great day for the Scots when he hit top form to overwhelm Welsh PBA qualifier Steven Harris in straight sets, 11-2 11-5.

Foster, just as Norfolk's Mervyn King did on Tuesday, peppered the jack with inch-perfect deliveries to which Harris had no answer – though the gritty Welshman never gave up, and put up stiff resistance in the second set.

At four-all after four ends, a tie-break looked a distinct possibility, but two Foster trebles put him out of reach, and he set up a second round encounter with the winner of this morning's clash between Jason Greenslade and wildcard entry Billy Jackson.