The Eagles led by seven at the break, the first time they have ever been in front at half time against a tier one nation at a World Cup, but Tolkin felt it could have been more as his side failed to gain control of the ball on their first four lineouts.
Scotland then scored five tries in the second half at Elland Road to cruise to a 39-16 win as USA kicked over just a solitary penalty in the second 40.
"We certainly had the opportunity (to be further ahead at half time)," Tolkin told Sports Mole after the match. "In the first quarter of the game we had some momentum and penalties getting us into attacking parts of the field, but we couldn't execute lineouts.
"We had the possibility of certainly putting the pressure on and perhaps then tries from that, but we'll never know because we didn't execute."
Defeat keeps the Eagles bottom of Pool B on zero points, with fixtures against South Africa and Japan to come on October 7 and October 11 respectively.