Williams, thanks to the return of Renault engines and major changes to the design team, has created a car that at times - if not all the time — has the potential of front-running performance. But while Pastor Maldonado has delivered strong but sporadic results, Senna has been generally off the mark.
Maldonado leads Senna 6-3 on grid spots, having claimed a pole position and made it into three top-ten shoot-outs (including the last two races). He has, however, had three sub-20th position starts (although they were due to a five-place gearbox change penalty in Bahrain, a series of collisions in Monaco and a meeting with the 'wall of champions' and a gearbox penalty in Canada). Senna, meanwhile, has yet to appear in Q3 and has qualified between 13th and 17th in all races, with six starts from the seventh row.
In terms of pure pace, taking their relative Q2 performances, Maldonado is on average 0.37s faster — and has been 0.6s ahead in three of the last four Q2 sessions.
In the races, Maldonado has scored 29 points against Senna's 18 — but that said, 25 of those points came from one victory whereas Senna has scored points on five occasions (for 6th, 7th, 9th and two 10ths). Maldonado has thrown away lots of points opportunities — most spectacularly in Australia when he lost sixth place by crashing out on the last lap with a rookie hot-headed mistake.
Both drivers have had their share of mishaps this season, but Senna's performances, in races at least, have perhaps been unfairly overshadowed by Maldonado's one moment of glory.
Qualifying that is Senna's problem, and he knows it — but it's not going to be an easy issue to solve.
His first issue is one of time — and there's not much he can do about that. He has been made to step aside for Bottas on six of the nine Friday morning practice sessions, and that has lost him a crucial one-and-a-half hours of running, during which time important set-up changes can be made that influence the whole of the race weekend. And there is no sign that Williams is going to stop giving Bottas the experience time for the rest of the season.
The second problem is driving style. In high temperatures, Senna says he cannot keep the tyres in the performance window — something that Jenson Button is struggling with too this year. Both of them have a smooth driving style that suits a neutral balance but with that the rear tyres go off quicker and the front tyres don't begin working quickly enough — creating a relative grip loss that explains some, if not all, of the qualifying differential between Senna and Maldonado.
In races, Senna has had a fair share of incidents — in Melbourne he spun on first lap; he hit Maldonado in Malaysia; he retired with brake problems in Bahrain; he was hit by Schumacher in Spain; and he collided with Kobayashi in Valencia.
However, the clash with Maldonado in Malaysia — which put him right to the back after a pit stop for repairs - gave him the chance to truly show what he can do — and he raced back to sixth place, his best finish of the season. If only he could qualify well and do that from the start.
After last week's Silverstone test, Bottas — who chose not to race in any other series this year - openly stated he feels ready and able to race in Formula One "now, if someone asked me to..."
Times in Q1 don't mean much, but of the six events Bottas has driven, four saw the young Finn faster than Maldonado.
If it's not now, the call is likely to come in 2013, meaning that assuming it does not come early, the rest of the season will be a fight between Senna and Maldonado to prove their worth.
Right now, Maldonado's headline victory and performances in qualifying (in which he has always been strong) put him on top but in terms of consistency, it is Senna who is hitting the mark.
In truth, although Senna has done 35 races he only sat in a decent car from Spa last year. Once Spa arrives, another excuse will disappear — but he's trying not to feel the pressure.
"There is always pressure on a driver, pressure is there every single time we're in the car," he said recently. "If I get qualifying right everything is going to become more straightforward."
That's a big 'if'. But, yes, if Senna can turn those qualifying issues around, the signs are there to suggest he could just turn things around.