Ivan Lendl watched on as Andy Murray started the defence of his Queen's title with a straight-sets victory over Nicolas Mahut after Fernando Verdasco claimed the scalp of Stan Wawrinka.
Murray announced last weekend that Lendl agreed to coach him for a second time, two years after the pair split, and the world number two began his grass-court season by battling past Mahut 7-6 (10-8) 7-6 (7-1) in the first round in London.
Mahut won the Rosmalen Grass Court Championships for a third time on Monday but was unable to pull off an upset a day later in top seed Murray's first match since losing to Novak Djokovic in his first French Open final.
Murray, eyeing a fifth Queen's title, made hard work of reaching round two, saving a set point in the first breaker and another three when serving to stay in the second set at 6-5 down before ending Mahut's resistence.
The Brit had to come from a break down in the first set to force a tie-break and trailed 4-1 in the second, but dug deep to thwart the unseeded Frenchman.
Wawrinka failed to hit the ground running on grass with Wimbledon fast approaching, suffering a shock 6-2 7-6 (7-3) defeat to experienced Spaniard Verdasco.
The world number five, who has employed Richard Krajicek for the grass-court swing, had a first-serve percentage of only 53 and crashed out after failing to convert any of his eight break-point opportunities.
Verdasco will now face Bernard Tomic, who beat last year's runner-up Kevin Anderson 6-3 6-4.
Tuesday also saw victories for Roberto Bautista-Agut, Adrian Mannarino, Donald Young and fifth seed Marin Cilic - who had to come from a set down to beat Feliciano Lopez.