Mercedes Motorsport boss Toto Wolff has upped the pressure on Valtteri Bottas for the 2018 Formula 1 season, claiming there is "no excuse" for him not to challenge teammate Lewis Hamilton.
The Finn made a strong start alongside the Briton last year following his late move from Williams but would tail off in the second half as a combination of struggles with car setup and simply being unable to keep up with Hamilton took off some of the shine.
He would hit back strongly in the closing races finishing second in Brazil and winning in Abu Dhabi, however, on just a one-year deal and with names like Daniel Ricciardo and Esteban Ocon being linked to his seat, producing those results more often is now a requirement from the Mercedes hierarchy.
"That's what he has to do," Wolff told ESPN. "If he can step up and challenge Lewis he has his place among the greatest drivers in F1, if he doesn't he's going to know it and there is no excuse."
The Austrian has a long history with Bottas, having been a part of his management team for much of his career as well as being a shareholder in Williams before switching to Mercedes, therefore, he has confidence the 28-year-old will respond.
"He is a Finn with a strong never-give-up mentality," he said. "Valtteri will improve his weaknesses and continue to work on his strengths. I expect him to come back strong with all the learning he has done during the season.
"I have no doubt we will see a better Valtteri in 2018."
Earlier this week, controversial former world champion Jacques Villeneuve described Bottas' performance as "embarrassing" and suggested Pascal Wehrlein would have been better, however, Wolff rejected the Canadian's opinion.
“We like working with Valtteri and with Lewis," he insisted. "The two fit well together. They have a good dynamic in the team and see no reason to change it."
Toto has claimed it would be better for Mercedes if there was a little more needle between Bottas and Hamilton, however, he doubts the former GP3 champion would resort to any Nico Rosberg-style mind games.
"That's not at all Valtteri's style," he believes. "Valtteri wants to do it on the track in the best possible way, he wants is to be benchmarked against a four-time world champion. He's brutally honest with himself."
Symonds: China strategy proves Ferrari o
Future of Belgian and Japanese GP's unce
Verstappen bemoans "less fun" F1 cars si
2018 could be a "legendary" season for F
Ferrari the possible target of new FIA d
Hamilton confident of Mercedes comeback
Haas team boss Steiner angers IndyCar wi
Perez still eager to get his second chan
Red Bull set Ricciardo deadline as big r
Massa: Williams put money first but it h
Haas owner sure budget cap will allow mo
Renault "reasonably pleased" in "nip and
Rosberg no longer part of Kubica's manag
Hamilton sets big target for future desp
Spanish media link Alonso to McLaren exi
Mercedes claim tyre performance the bigg
Verstappen moves on from China as Red Bu
Rosberg recommends rivals exploit curren
Planned Renault engine upgrades could ex
FIA director Whiting reveals possible so
Bottas the only positive for Mercedes in
Brawn bemoans gap between top teams and
Alonso finds questions about ex or rival
Ricciardo remaining calm over future des
Jos Verstappen offers advice to son Max
McLaren claim actual 2018 car will debut
Williams warns F1 of dire consequences w
Could Ricciardo replace a retiring Hamil
Vettel reveals Safety Car grievance duri
Hamilton & Lauda among Verstappen critic
Alonso plays down significance of brief
Bottas sure Chinese win was possible wit
Ricciardo offers typically exuberant res
Deflated Hamilton felt in "no-mans land"
No hard feelings between Vettel & Versta
Ricciardo takes remarkable victory in dr
Chinese GP: Vettel beats Raikkonen to se
Ferrari reveals Liberty deadline for dec
Alonso rejects talk of McLaren move, pra
Hamilton believes Red Bull not "at the s
Chinese GP: Vettel leads Ferrari 1-2 as
Chinese GP: Hamilton pips Raikkonen in t
Chinese GP: Hamilton sets rapid early pa
No extra practice for Kubica amid Willia
Gasly was giving "credit back to Honda"
Ricciardo would have "100 percent" attac
Vettel still sure Mercedes are the team
FIA announce next step in response to re
Hamilton and Verstappen shake hands as "
Mercedes boss reveals surprising driver
Bahrain an example of why F1 drivers con
Red Bull want Renault improvement after
Alonso calls for McLaren improvement aft
Ricciardo left devastated after early Ba
Mercedes boss rueful after Bottas comes
Gasly revels in "unbelievable" run to fo
Hamilton & Verstappen hit out at each ot
Injured Ferrari mechanic undergoes succe
Bahrain GP: Vettel holds off charging Bo
Hamilton points to heat and engine modes
Alonso admits McLaren had "negative surp
Verstappen blames engine anomoly for Bah
Bahrain GP: Vettel leads Ferrari 1-2 in
Reported budget cap figure for 2021 "muc
Verstappen would consider ban on Mercede
Vettel sure of further Ferrari gains aft
Ricciardo reluctant to see Bottas penali
Hamilton hit by five-place grid drop for
Bahrain GP: Ferrari move to the front as
Bahrain GP: Ricciardo sets surprise earl
Details emerge as F1 bosses reveal 2021
FIA seek measures to improve F1 overtaki
Hamilton & Vettel disagree on current pe
Hamilton watching Liberty as he ponders
Liberty make one-off deal for grid girls
Haas reveal measures to avoid repeat of
Alonso talks McLaren expectations and wh
New Hamilton/ Mercedes contract "as good
Sauber boss Vasseur warns F1 teams could
Toro Rosso drivers set for modified Hond
Mercedes boss Wolff admits Australia los
Hulkenberg positive Renault success will
Brawn fires back at "personally offensiv
Spanish media claim McLaren want rid of
Sirotkin rejects Villeneuve's outlandish
Bahrain GP Preview: Hamilton seeks reven
Monaco could extend F1 track thanks to n
Sainz trying not to be put off by loan s
Ricciardo keen not to "disrespect" Red B
A qualifying sprint race part of propose
Alonso sees McLaren joining big three te
FIA's Whiting sees no reason to act on t
Red Bull advisor Marko defends his Webbe
Bottas insists Mercedes face a "tough se
Vettel brushed off Hamilton's post-quali
Gasly encouraged by "big, big" Honda eng
Ricciardo: Slower F1 acceptable with bet
Lewis Hamilton to quit F1 for Formula E
Renault to call for engine development f
Vergne reveals his first reaction to Har