Paisley's Dean Robertson produced an electrifying finish, birdieing five of the last six holes, to break a log-jam on the leaderboard at the Benson and Hedges International Open last night.

The former Scottish amateur champion's form in carding a five-under-par 67 was in keeping with the conditions, thunderstorms delaying play at the Oxfordshire course for six-and-a-half hours. More than half the field must return at 7.45am today to complete their rounds.

There was no sign of the fireworks which were to follow when the slightly-built 27-year-old left the twelfth green at level par. Then he hit a No.6-iron to 18 inches on the 171-yard thirteenth to miss out on a #80,000 Honda car. But the fuse had been lit, and his confidence fuelled.

A wedge to two feet on the next brought another birdie and then he picked up another 2 with a No.5-iron to six feet on the 210-yard fifteenth. Putts of three feet and 10ft on the last two greens were confidently drilled centre-cup for an inward half of 31.

His best round of a miserable season left him one stroke clear of former Walker Cup team-mate Bradley Dredge, and the Italian Massimo Florioli.

Robertson revealed: ''I practised really hard throughout the winter and came out expecting great things. Instead I played poorly, had a disastrous start, and my confidence was shattered.

''As things got worse, my swing got quicker and quicker, and I was mistiming most of my shots. Recently I have been working with two coaches to correct the fault.

''Having missed the cut three times before in this tournament, which is the first big one in this country, I feel it owes me something. I played well today and need a few more rounds like this to restore my confidence fully. ''But I'm not counting my chickens - this game can jump up and get you.''

It also helped that Robertson had his caddie, Brian Byrne, by his side again to calm him. He has been missing for the 11 weeks after dislocating a knee in Africa.

A strong Scottish challenge materialised from other unexpected quarters.

Burhill's Gary Orr built the foundation for a 69, which is one of his best opening rounds for many a day, with a brilliant eagle on the 498-yard seventh. ''I hit a No.3 wood to four feet, which was the shot of the year for me,'' he said. ''It had been an up and down start until then, and that set me up.

''Mostly I have poor opening rounds which leave me too much to do. You cannot be too far back with the scores that are being posted these days. You need four good rounds.

''I am pleased with that because I played solidly. I have been working a lot on my putting and it paid off. The course played long but it was good for scoring.''

After finding the rough off the tee on the eighteenth, Orr could only hack out leaving himself 60 yards short of the green. But he saved par with a sand-iron to 10ft and then a perfectly weighted downhill putt.

Lee Westwoood would have provided further evidence of his remarkable talent but for inexplicable putting lapses. The Ryder Cup player had to settle for a 71 after missing six putts from inside 15ft.

''I was not starting the ball where I was aiming. With a reasonable day on the greens, I'd have shot 66 at worst. I have just had one of those days.

''But I am still a bit rusty after the US Masters. Those four weeks in the US were very exciting and hectic, but they took a lot more out of me than I expected.

''However, it is nice to sit down to dinner knowing that I am only four shots off the lead. I really thought that someone would take the course apart in these conditions.''

The Dane, Per-Ulrik Johansson, who posted a 70, also had a frustrating day with the flat stick and blamed it on the fact that he did not have enough time to prepare before setting out.

He has now fully recovered from the mystery virus which forced him to withdraw before the final round of the World Cup last year at Kiawah Island.

The illness, which caused fainting turns, has forced a re-think and he has dramatically cut back on his playing schedule.

''I am now listening to my body. Before I tended to push myself to the limit. Now I rest when I need to, and I am swinging well and feeling good.''

When play was halted due to failing light at 8.30pm, Colin Montgomerie stood at one under par after nine holes, with playing partner Andrew Coltart two shots worse off.

Englishman Paul Affleck was four under, while Dane Thomas Bjorn was out in 33, as was Irishman Padraig Harrington. Scores: (GB and Ireland unless stated):

(*denotes amateur)

67 - D Robertson.

68 - M Florioli (Italy), B Dredge.

69 - B Davis, D Lynn, A Sherborne, P O'Malley (Australia), M Hallberg (Sweden), G Orr, P McGinley, S Luna (Spain), R Claydon, D Carter.

70 - N Joakimides (France), W Westner (South Africa), M Gates, J Lomas, P-U Johansson (Sweden), S Leaney (Australia), D Clarke, G Brand Jr, P Quirici (Switzerland), R Davis (Australia), M Gronberg (Sweden).

71 - P Eales, R Derksen (Holland), I Woosnam, L Westwood, W Riley (Australia), P Lyons, R Allenby (Australia), I Pyman, P Fulke (Sweden).

72 - *J Rose, A Wall, J-M Olazabal (Spain), T Johnstone (Zimbabwe), J Haegg-man (Sweden), C O'Connor Jr, K Tomori (Japan), M Campbell (NZ), P Walton.

73 - T Gogele (Germany), R Jacquelin (France), D Cooper, F Henge (Sweden), D Chopra (Sweden), G Owen, C Rocca (Italy), M-A Jimenez (Spain), C Hainline (US), R Boxall, J Townsend (US), R Wessels (Rsa), J Rivero (Spain), R Muntz (Holland).

74 - R Burns, S Webster, M James, P Mitchell, T Levet (France), N Henning (South Africa), D Gilford, R McFarlane, M Long (NZ), V Phillips, E Darcy, I Garbutt.

75 - M Roe, R Coles, HP Thuel (Germany), S Richardson.

76 - N Vanhootegem (Belgium), R Chapman, A Forsbrand (Sweden), J Coceres (Argentina).

78 - R Russell, O Eliasson (Sweden).

q 78 players to complete first rounds today.