Mercedes finished with the fastest time in both practice sessions on Friday, with Valtteri Bottas leading the way in the morning while Lewis Hamilton took top spot in the afternoon.
Although the Silver Arrows were the team to beat, Max Verstappen made sure his presence was felt as well thanks to the second fastest time in both sessions which means we should expect a fascinating battle for pole on Saturday.
It will be all the more interesting given Ferrari's strong showing as well, while a new team emerged as the midfield battle heats up in Portugal.
Mercedes v Red Bull still too close to call
In a trend that will continue all season, it was Mercedes and Red Bull who led the way yet again. The rivals have split the opening two races in Bahrain and Italy, and all signs point to Sunday's winner coming from either team.
However one storyline that did emerge is that for the first time all season, it looks as though the Silver Arrows may have gotten the better of Red Bull on track after Bottas registered the fastest time in FP1 with Hamilton claiming FP2.
It isn't the first time Mercedes have finished ahead of Red Bull this year - Lewis won the Bahrain GP and took pole in Italy, while Bottas finished with the fastest time in both practice sessions at Imola. However those accomplishments were aided by some slip ups by the Milton Keynes outfit.
That didn't happen on Friday, with Mercedes looking like the more comfortable car. In the end Verstappen finished second in both sessions, meaning the gap between the teams remains marginal.
Track conditions could play a part in who comes out on top, with several drivers noting they had difficulties with the slippery tarmac. Hamilton also mentioned that the afternoon session was warmer and windier than the morning, making it difficult for drivers to work on the balance of the car.
"I don't know what Max's lap was like in FP2 but mine wasn't perfect so we definitely have some time to come from the car and improvements to make," Hamilton said after FP2. "But I'm sure Red Bull have too."
As for Verstappen, the Dutchman believes tyre temperature will play a big role as to which team finds the edge on Saturday.
"It’s very tricky out there and not easy to switch the tyres on which is a shame because it seems to be all about tyre preparation and temperature," Verstappen said. "It’s the same situation for everyone so we just need to make sure we are on top of the car so we can make the best out of it.
"It seems tight with Mercedes this weekend again and the car felt alright but we still have some work to do ahead of tomorrow, that’s for sure.”
Ferrari gunning for the front row?
Ferrari have looked much improved at the opening two races of the season, and that trend continued on Friday.
The Scuderia look like the best of the midfield runners, so much so that they are even challenging Red Bull and Mercedes. Charles Leclerc and Carlos Sainz both posted impressive lap times in FP1 and FP2 respectively. The Monegasque finished just 0.2s behind Botta's top time, while the Spaniard was 0.360s behind in FP2. Their pace didn't go unnoticed.
"The single lap looks really close with Red Bull but Ferrari were also consistently around our pace so we'll prepare ourselves for another close fight tomorrow," Mercedes trackside engineering director Andrew Shovlin noted.
Leclerc noted it was a good start to the weekend for Ferrari, though he feels the team are looking more competitive during short runs rather than race pace.
"We completed the whole programme we had planned and it looks like we are quite competitive," said Leclerc. "The short runs were good, the long-runs a little bit less so and I think that is the main weakness for me today so I still have to work on that."
As a result Ferrari could be more competitive on Saturday, though Sainz doesn't want to put too much stock into Friday's times.
"We are fully focused on tomorrow," Sainz stated. "We saw in Imola that Friday may be misleading when comparing our one lap pace to our competitors, so we are wary of that."
Alpine on the rise while McLaren fall back
Alpine and McLaren have seemingly swapped positions when it comes to performance, with the French team having a much stronger day on Friday compared to the Woking outfit.
Fernando Alonso's fifth place was his highest placed result since making his return, with the Spaniard remarking it's the most comfortable he's been all season. More encouraging for Alpine is the fact that he finished just 0.035s clear of teammate Esteban Ocon in sixth, showing the overall package is looking good in Portugal.
Alpine's Friday was much different to that of McLaren, who didn't look like the team the finished on the podium in Italy.
Their best lap of the day came via Daniel Ricciardo in the afternoon, 0.581s back of Hamilton. However the rest of the day the team were in and around one second slower of the top time, a fact that doesn't have Norris all that confident heading into Saturday practice.
"If they're [Ferrari] ahead of us it's not a surprise," Norris told Sky Sports. "We had a big gap to the Alpine over the last two weekends, but this weekend they seem a lot more competitive.
"It makes the race - or the chance to get into Q3 - a lot more difficult. It's two more cars we might be racing, so it's exciting but it makes life a bit more tricky. It's a bit tougher than we expected and a bit tougher than we want."
With the fight in the middle of the grid so tight, McLaren look like they have the work cut out for them as they try to maintain third in the constructors' standings this weekend.
Aston Martin yet to impress despite close grid
While Alpine have taken a step forward in Portugal, it looks as though Aston Martin are once again on the outside looking in when it comes to the midfield battle.
Lance Stroll only cracked the top 10 in the afternoon after finishing 11th in the morning, while Sebastian Vettel looked uncomfortable yet again and could only manage the 16th and 15th fastest times.
There are some positives for Aston Martin, as both Stroll and Vettel completed a healthy number of laps. It's certainly an encouraging sign for the German in particular, who needs as much time as he can get in the car.
The top 12 were separated by less than a second, meaning that some mistakes by their competitors and some small improvements overnight could see Aston Martin put in a strong showing on Saturday.