In a game that threatened so much, the biggest moment of the Premier League International Cup group stage fixture came when Porto's Marcus Abraham was shown a straight red card after a skirmish towards the corner flag, which saw a member of the Portuguese coaching staff also sent off.
After over a month away, Leicester City's Development Squad returned to action in a competition where they headed into the evening with three points from their opening two games.
Coach Ben Petty made four changes from the 2-0 defeat to Valencia in the last group stage match, with Zach Booth, Tawanda Maswanhise, Kian Pennant and Terrell Pennant all starting the match.
It took 10 minutes for either side to see sight of an opening, when Leicester's left-hand side looked to cause problems with T. Pennant and Maswanhise, but it was the Portuguese side who would see the clearest opening at goal in the early stages.
Arlo Doherty ran out of his box to claim the ball, but under pressure from Abraham, City's 'keeper would lose possession, and Porto had a golden chance to take the lead. Unbelievably however, the No.98, with only a defender planted on the goal line, managed to strike the woodwork, keeping the scores level.
Following this missed opportunity, both teams looked to break the deadlock, T. Pennant coming closest for the Foxes when he tried to curl an effort past Roko Runje in Porto's net, but the 'keeper made the save.
Just past the half-hour mark, the visitors were in again when Vasco Sousa followed up on a strong save from Doherty, but he couldn't direct his attempt on target, and saw his effort flash past the post.
Minutes before the break, it was Leicester who looked likely to score, and almost did when T. Pennant took aim from the edge of the box. Catching the volley nicely, the effort looked to have the 'keeper beat, but the ball flashed past the outside of the post, hitting the side-netting on its way out of play.
The first chance from the restart came for the visitors, when a whipped in cross was met by the head of Gabriel Brás, but Doherty did well to leap across his goal and claim the goal-bound effort.
The Foxes continued to probe themselves, and came closest when Ethan Fitzhugh tried to dip a free-kick up and over the wall. The effort had Runje scrambling, but the set-piece was probably too close to the goal for Fitzhugh to cause any real danger.
This wasn't to be City's only chance of the half as a pacey front three were always on the look out to cause problems, and T. Pennant looked to do just that when the forward fired an effort towards the Porto goal.
In the final 20 minutes of the match, things started to get heated between the two sides, and following a skirmish in close proximity to the corner flag, two members of the Portuguese club were shown red cards.
The first to striker Abraham, with the second being displayed to a member of the Porto coaching staff.
On the front foot against 10 men, Leicester pushed hard during the last 10 minutes, in the hope of finding a way through a resilient Porto back-line. T. Pennant once again broke in behind on the left wing, before forcing a save from Runje.
But despite a lot of possession in the final stages of the match, the Foxes struggled to find a way through and would have to settle for a draw in Seagrave. However, after falling to a 2-0 defeat to Valencia in the last round of fixtures, coach Petty will be happy to take a point and clean sheet, after over a month out.
Major moment – Tempers flare
In quite an even-battled contest, many people leaving Seagrave will remember the red card the most. Following a challenge on the far side of the pitch, Marcus Abraham, along with a member of the Porto coaching staff received their marching orders from referee, Alan Dale.
Who impressed? – Ethan Fitzhugh
Against an extremely physical opponent, the Foxes had most luck in front of goal, from Fitzhugh's set-pieces. Coming close with a direct free-kick himself in the second half, the midfielder caused problems for Porto's backline with his deliveries.
Where do we stand? – Fifth in Group A
Leicester's youngsters climb to fifth in Group A of the Premier League International Cup following a goalless draw with Porto. City have picked up a total of four points from three games.
Coming up – Chelsea (H)
City's youngsters will return to action in the new year, when they take on Chelsea in Premier League 2 Division 1 action, at LCFC Training Ground on Monday 9 January (7pm kick-off).
The details...
City: Doherty; Wormleighton, Appiah (C), R. Nelson (Grist 73'), Flynn; Cover, Booth (Briggs 73'), Fitzhugh; T. Pennant, Maswanhise, K. Pennant.
Subs not used: Chibueze, Joseph, Nyoni.