The Hoops joined Group G winners Barcelona in the next round after rivals Benfica could only manage a goalless draw in the Nou Camp.
Lennon's side became the first Scottish side to achieve ten points in the competition as they progressed out of the group stages for only the third time in their history.
Celtic could now face Paris Saint-Germain, Bayern Munich, Manchester United, Borussia Dortmund, Malaga, Shakhtar Donetsk or Schalke when the draw is made on December 20.
But Lennon, who was leading his side for the first time in the competition, said his players feared no one after successfully negotiating a tough group.
"It is going to be really tough whoever we face as we are going to get one of the top teams in the groups," the Celtic manager said.
"You just don't know what shape teams are going to be in two or three weeks time.
"But we are there and we're going to enjoy it. We want to progress as far as we can in the competition. Who knows where it might take you?
"The spirit is fantastic, we've got some quality players, they've put everything into the group and they've grown as the campaign has gone on.
"Some of them have enhanced their reputations no end but as a collective they've got great belief in themselves and as I said who knows where it might take them,
"But we look forward to the draw. It is very exciting times for everyone at the club and we have got something we can really get our teeth into in the new year."
Many commentators wrote off Celtic's chances when the draw for Group G was made back in August.
However, the Hoops achieved their first away win in the competition as they triumphed 3-2 in Moscow and remained unbeaten at home, which included a famous 2-1 win against Barcelona at Parkhead.
With big-spending English giants Chelsea and Manchester City failing to qualify for the last 16, Lennon says his side had proved the doubters wrong.
"I said at the start - and people laughed at me - when they asked me what my target was and I said I wanted to qualify," the Celtic manager said.
"I think you could see the players progressing here last year. We have got some really talented players we felt could play at European level.
"This is the premier event and we have had some rough times through it but we are unbeaten at home.
"In the two qualification games we showed great composure and at times when it was backs to the wall we showed great defensive qualities when we needed to which was probably alien to some of the players.
"There were some great individual performances but as a team throughout the games they performed brilliantly.
"They have justified beating Barcelona now. I didn't want them to be the team just remembered for beating Barcelona.
"They have beaten Barcelona and they have qualified for the last 16 so it is a fantastic thing for them to have in their caps."
At Celtic Park, Gary Hooper pounced on a Spartak defensive error to fire the Hoops into a 21st minute lead before the Russians grabbed an equaliser in the 39th minute when Ari showed good composure to lob Fraser Forster from a difficult angle.
With just 10 minutes remaining Samaras won a penalty after a push in the box from Kirill Kombarov and Commons kept his cool to smash his spot-kick in off the bar, although his manager admitted he didn't see the vital penalty.
"I didn't watch it, I turned my back on it. I've seen the last couple of penalties and we've missed them so I thought I would just wait and hear if the roar went up," Lennon said.
"He showed great mental strength to step up there and take it. Obviously I'm sure he was aware of the significance of the penalty but it epitomised his night.
"I thought he had a fantastic game for us. You want to celebrate but you know there is still a bit of work to do in the game and we saw it out very well."
Source: AFP
Source: AFP