Tom Watson is well in contention at Newcastle

And he illustrated his ability to cope with links golf once more when he added further birdies at 12th and 13th.

He went into the rough and dropped a couple of shots on the 15th.

But he retrieved the situation with successive birdies on 17th and 18th.

"It is unbelievable," said Sugai, who has won four times on the Japan PGA Tour and three times on the Japanese Seniors Tour, but has done little of note outside his home country.

"I have a four-shot lead, but maybe it should be 20. I will certainly be looking over my shoulder at the weekend."

Sugai's nearest challenger is Scotland's John Chillas who produced his second successive 69 to finish on 138.

One stroke back is Tom Watson who kept firmly in the running with a two-under-par 69.

'Solid round'

Watson, the five-times British Open champion, began the day with a birdie on the 522-yard par five first hole.

He then fired 13 consecutive pars before securing his second birdie of on the 450 yard par four 15th.

He ended with three more pars.

"I played a solid round of golf," said Watson.

"I hit the ball a lot better than yesterday so I can look forward to the weekend."

Tony Jacklin followed his first-day 81 with a 75 and missed the cut.

Leaderboard after two rounds

134 N Sugai (Jpn) 67 67; 138 J Chillas 69 69; 139 T Watson (USA) 70 69, J Irwin (Can) 71 68; 140 R Weir 68 72, K Takahashi (Jpn) 71 69; 141 J Bland (Rsa) 71 70; 142 J Morgan 72 70; 143 B Verwey (Rsa) 72 71, M Gregson 72 71, B Vivian (Nzl) 71 72, N Job 76 67, M Ferguson (Aus) 72 71, S Ebihara (Jpn) 72 71, C O'Connor Jnr 73 70, T Allen 70 73; 144 D Oakley (USA) 76 68, N Coles 74 70, K MacDonald 74 70, R Metherell (Aus) 75 69, J Grace (USA) 72 72; 145 B Charles (Nzl) 73 72, D Durnian 73 73, B. Jones (Aus) 72 73, M Bembridge 72 73, J Bruner (USA) 73 72.