The Portuguese coach - who replaced Otto Rehhagel after the 2010 World Cup when they exited in the first round - was not content because he said he had demanded a win and they had come up short.
"I said we were going for a win so I am not satisfied," said the 57-year-old.
"However, I am very proud of my players."
However, he was kess than happy with Spanish referee Carlos Velasco Carballo's decision to send off Werder Bremen defender Sokratis Papastathopoulos for a second bookable offence shortly before half-time.
Papastathopoulos was adjudged to have brought down Polish midfielder Rafal Murawski.
But television replays suggested contact was minimal and Murawski may have lost his footing, after pre-match rain lashed Warsaw.
"I don't think it was justified that Sokratis was sent off with two yellow cards. But still we succeeded in keeping the pressure on," said Santos.
"I totally accept the decision of the referee but it made it very difficult for us.
"Normally we play a more attack minded game but we had to change our tactics after the player was sent off."
Despite this his inspired decision to send on Dimitris Salpingidis at half-time paid rich dividends as he scored six minutes later and indeed the coach admitted that his players had been more effective when down to 10 men.
"We didn't do a great job in the first 20 minutes... Poland were quick on the attack but we improved. We started to control the ball. We got into Poland's half more then Sokratis was sent off.
"We were confident on the pitch. We always thought we could get in the game again. The players were very good in the second half.
"We scored a goal and obviously had a chance at the end of the game to win it but we didn't, so that's football."
The chance that went begging was a penalty from captain Giorgos Karagounis, which he had saved by Przemyslaw Tyton in his first touch after he replaced first choice keeper Wojciech Szczesny, who also got on the wrong side of the Spanish referee with a trip on the lively Salpingidis in the 69th minute.
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