Tottenham Hotspur manager Andre Villas-Boas believed his side fully deserved the win at Cardiff City Stadium despite the only goal coming in the third minute of injury time.
"There could only be one winner," said Villas-Boas.
"We played so much football it would have been unfair to leave here with only one point.
"We got our reward in the end, but with the chances we created, if it wasn't for Marshall, it could have been a more comfortable game.
"You worry it can be one of those games. We played so open and sometimes on the counter they had a chance. But today, more than maybe any other game, we deserved the win.
"It's satisfying as I don't see many teams coming here and winning against a team who are well organised and well managed."
Cardiff felt they had twice come out on the wrong end of decisions by the officials.
The first came when Hugo Lloris appeared to handle outside his area as Fraizer Campbell attempted to round him, although replays suggested it was a very tight call.
The second saw Ben Turner's header from a corner chalked off after Aron Gunnarsson was adjudged to have impeded Lloris.
But Villas-Boas felt the officials had got it right on both counts.
He said: "I haven't seen it (the first incident), but I understand he was right on the limit. I'm not sure if there is some controversy there.
"Most people I have spoken to told me his hand is right on the line. I think if that is the case the referee made the right decision."
Of the disallowed goal, he added: "I think it was a foul for holding Hugo's arm. We spoke about it between us at half-time and he said he would have been fine if he had not been fouled."
Cardiff boss Malky Mackay admitted he was disappointed at seeing Turner's header ruled out, but was more upset with his side's finishing than Lloris' early challenge on Campbell.
"Hugo Lloris will see it tonight and realise he is a lucky man and the referee will be disappointed in his decision," said the Scot.
"If you look at it again, it is Lloris who has his hand on Gunnarsson and then completely misses the track of the ball so for me it is a clear goal.
"The incident with Fraizer is one people will look at whether it was out or in, but we had a one-on-one and Fraizer is invariably brilliant at those, and he is more disappointed he did not skip by him. Whether it was a foul or not is open to question.
"We had some real good chances, but it's about being clinical."
Mackay also praised Marshall's display, but felt the defeat shows the challenge his side face in the top-flight.
"I don't think what you deserve comes into it, that's the harsh reality, they were clinical in the last minute and we weren't in the first minutes when we were through on goal," he said.
"David is a top goalkeeper, I think their goalkeeper cost £9million and I look at my keeper today and see him step up. He was the best in the Championship and he is in the Premier League, back in the Scotland squad and he has looked so comfortable in the games we have played against some top teams."