Buckland and his Tigers team-mates were convinced the England Saxons international had scored under the posts, which would have left Andy Goode with an easy kick to complete victory. But referee Roy Maybank ruled against a touchdown and signalled full-time as Sarries celebrated a 22-16 victory.
Tigers had fought back from 10-3 and 19-6 down to rally in the closing stages with a try from replacement Goode, who also converted and kicked a penalty with just over 10 minutes remaining to bring the scores back to 19-16.
Head coach Pat Howard said: "We took time to get going. We had a bit of trouble in the line-out early on and there was a shortage of possession. We also gave away a cheap try and they got on a bit of a roll. The penalties just before half-time allowed them to pull away.
"But then we got some real momentum, the scrum more than held their own, and I am really proud of the guys because they showed a lot of fight and grit. And we nearly won it at the end."
Leo Cullen, captain in the absence of Martin Corry, said: "The lads put in a lot of effort, they fronted-up well. Saracens are a team that like to drive and take teams on in the scrum but I thought the lads stood up well. I certainly could not ask anything more of them in the second half.
"From where I was stood, I thought it was a try at the end. But there were plenty of positives to take out of the game and now we have to look ahead and try again in six days' time against London Irish."