Middlesex 290 for 6 (Robson 84, Eskinazi 82) v Hampshire
The pair added 105 for the second wicket with both reaching their milestone with unassuming yet not run shy stays at the crease.
But Hampshire, who bowled with a man light for the majority of the day after Fidel Edwards went off injured, battled hard in the evening session to even up the contest - after turning 220 for 2 into 290 for 6 at the close.
James Franklin decided to have a toss and duly won it and elected to bat - the Middlesex captain looking down not up with overcast skies overshadowed by a decidedly flat looking pitch.
There were cheers from supporters around the ground as a steward unfurled and raised a "Middlesex County Champions 2017" flag above the away dressing room.
Robson has a knack of scoring early season runs - with his first three scores of last season 231, 106, and 99 disproving the general thought of April suiting the swing bowlers.
He began this knock in style clipping Edwards through midwicket to the boundary with the first delivery before following up with two further fours soon after.
But the fast paced opening was dulled as Gareth Berg and Kyle Abbott tidied up - with Edwards forced to sit out the rest of the day after his 21st over hamstring injury, after previously pulling out of a delivery in the run-up.
Robson lost his opening partner Gubbins to a corking ball from Edwards when the fast bowler found some late movement to take the edge before second slip Rilee Rossouw pulled off a stunning low catch.
Robson was dropped by Rossouw on 40 which saw the South African miss the rest of the day with a hand injury. He continued to cut and clip off his legs in text book style reaching his fifty in 82 deliveries. After a century stand with Eskinazi, Robson finally departed for 84 when he nicked Berg to Jimmy Adams, standing at second slip in place of Rossouw.
Dawid Malan accompanied Eskinazi, who reached his third first-class fifty in 102 balls, with the former smashing two sixes.
The evening found Hampshire finally turn a reasonably one-sided day around with four wickets falling in the session. Firstly, Malan guided the impressive Brad Wheal to Sean Ervine at first slip, before the Zimbabwean bowled Eskinazi for 82 three overs later - the ball clipping the very top of off-stump.
Adam Voges, who suffered a head injury at the Ageas Bowl last year, scored 24 quickly before he chopped Kyle Abbott onto his own stumps. John Simpson struggled by scoring just nine in 58 balls before he carelessly drove Wheal to substitute fielder Mason Crane at point.