Analysis: The fourth is strong with Force India - will Williams recover from Spanish woes?

Force India didn't party much on Sunday night after being hit with a suspended €25,000 fine by FIA Stewards for failing to comply with Formula 1's new numbering regulations - but it's clear that the only number the pink outfit cares about is fourth.

The fight to be at the top of the midfield is just as competitive as the gripping lead battle this season, at times impossible to predict, as Williams, Haas, Force India, Toro Rosso, and Renault spar with all their might.

A spectacular fourth and fifth place finish in Spain continues Force India's 100% points-scoring record this season so far as Esteban Ocon finished with a career-best fifth, a place behind the ever-reliable and much sought-after Sergio Perez. That was another 22 points in the bag on a day when Williams scored nothing.

Perez and Ocon's latest success brought the team closer to Red Bull as Max Verstappen recorded a DNF, which is unprecedented seeing as Force India has downplayed its fourth-place credentials repeatedly, let alone any improvement on that.

Perez said, "I think Williams and Renault are a bit ahead, Toro Rosso as well," to Motorsport.com after the race in Bahrain last month in which he qualified 18^th but finished seventh.

Behind Ocon was former Force India driver Nico Hulkenberg, sixth in the Renault and even Pascal Wehrlein of Sauber managed to score points after a convincing one-stop strategy race, having recovered from his early season injuries to earn an eighth place finish this weekend.

On the other hand, Williams, who expected to hold fourth in the constructors' championship, are losing the battle for the coveted place, sitting far behind in sixth at the moment as rookie Lance Stroll finished 16^th and Felipe Massa three places ahead for the Spanish GP.

Spanish struggles

Massa's downfall started and ended with his Turn 2 puncture on the opening lap after contact which sent McLaren's Fernando Alonso careering through the gravel. It was a racing incident and no blame was apportioned, but this made a points finish impossible for the briefly-retired Brazilian.

"His pace in clean air was very strong: He was matching Daniel [Ricciardo] lap-for-lap on his first stint. I think we had the potential to have a very good result," said Williams' Chief Technical Officer Paddy Lowe after the race.

Massa's gap to Ricciardo only increased by 2.54 seconds after that first unfortunate pitstop. Massa's race start was unlucky but there are still questions around Stroll.

It was a sorry sight for the young Canadian, who at one point was more than 50s ahead of Massa and even after having taken one fewer pitstop than the veteran, he finished more than 11.5s behind. Moreover, on lap 52, Stroll was overtaken by Marcus Ericsson whose Sauber is equipped with last year's Ferrari engine.

Running on medium compounds pushed Stroll further down the field, his times dropping off below the 1m32s mark while Massa was lapping nearly six seconds faster on each of those final three laps.

What's reassuring for Stroll is that his fastest lap was just over 0.3s slower than Massa's and he wasn't completely off the pace on soft tyres.

Williams' engine also recorded the fastest speed trap time, at 211mph - 17mph faster than that recorded by Hulkenberg's Renault - which may be a cause for concern for its midfield rivals as they race on power-hungry circuits like Montreal and Baku next month.

Stroll now has his work cut out for the Monaco GP, which he may have to write-off as a learning experience this year.

"In reality, nothing compares to Monaco," said his team-mate to Le Journal de Montreal.

"Monaco is one of the toughest tracks of the season. Probably the most demanding of all, in fact. There are still problems for seasoned drivers.

"Lance is going to have a hard life in Monaco," he continued.

Midfield mastery

Monaco has been a rich hunting ground for Force India in recent years. However Ocon has never raced in the Principality and it's fair to say the learning curve will be as steep for him as it will be for Stroll.

Perez, on the other hand, took a podium as he finished third in the 2016 Monaco GP and while repeating that may be a tough ask, it's expected that Force India should consolidate their top-four spot on May 28, especially as Fernando Alonso will not be charging hard in the McLaren on the only track where they could pose a real threat for the foreseeable future.

All eyes will be on this fascinating battle after Monaco, as teams scrabble to implement further upgrades for the Canadian race. Williams updated its aerodynamics and chassis last season and the same could happen in June, and again, the long straights should suit the FW40s.

But Force India, with a 32-point advantage over fifth-place constructor Renault, have little to worry about for now.

The team may have clocked up a suspended €25,000 fine for improper display of numbers after the Spanish GP, but Force India's problems seems incomparable to those that rivals Renault, Williams and Toro Rosso are facing in that battle for midfield supremacy.

Do you think Williams will recover or is Force India untouchable at the top of the midfield? Have your say in the comment section below or on JA on F1's Facebook.